diff --git a/DESCRIPTION b/DESCRIPTION
index 92365d0d..599da379 100755
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -67,8 +67,10 @@ Collate:
     'DataSurvival.R'
     'DataJoint.R'
     'Grid.R'
+    'GridEven.R'
     'GridFixed.R'
     'GridGrouped.R'
+    'GridManual.R'
     'GridObserved.R'
     'constants.R'
     'StanModule.R'
diff --git a/NAMESPACE b/NAMESPACE
index cf2ef095..dbeade23 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -1,11 +1,15 @@
 # Generated by roxygen2: do not edit by hand
 
 S3method(as.CmdStanMCMC,JointModelSamples)
+S3method(as.QuantityCollapser,GridEven)
 S3method(as.QuantityCollapser,GridFixed)
 S3method(as.QuantityCollapser,GridGrouped)
+S3method(as.QuantityCollapser,GridManual)
 S3method(as.QuantityCollapser,GridObserved)
+S3method(as.QuantityGenerator,GridEven)
 S3method(as.QuantityGenerator,GridFixed)
 S3method(as.QuantityGenerator,GridGrouped)
+S3method(as.QuantityGenerator,GridManual)
 S3method(as.QuantityGenerator,GridObserved)
 S3method(as.StanModule,JointModel)
 S3method(as.StanModule,Link)
@@ -27,8 +31,10 @@ S3method(as.list,DataJoint)
 S3method(as.list,DataLongitudinal)
 S3method(as.list,DataSubject)
 S3method(as.list,DataSurvival)
+S3method(as.list,GridEven)
 S3method(as.list,GridFixed)
 S3method(as.list,GridGrouped)
+S3method(as.list,GridManual)
 S3method(as.list,GridObserved)
 S3method(as.list,Link)
 S3method(as.list,LinkComponent)
@@ -113,8 +119,10 @@ export(DataJoint)
 export(DataLongitudinal)
 export(DataSubject)
 export(DataSurvival)
+export(GridEven)
 export(GridFixed)
 export(GridGrouped)
+export(GridManual)
 export(GridObserved)
 export(JointModel)
 export(Link)
diff --git a/R/DataJoint.R b/R/DataJoint.R
index 943932fa..ba6c06c3 100755
--- a/R/DataJoint.R
+++ b/R/DataJoint.R
@@ -188,7 +188,7 @@ subset.DataJoint <- function(x, patients, ...) {
     dat <- data.frame(
         time = data[["event_times"]],
         event = as.numeric(seq_along(data[["event_times"]]) %in% data[["subject_event_index"]]),
-        patient = names(data[["pt_to_ind"]])
+        patient = names(data[["subject_to_index"]])
     )
     subset_and_add_grouping(dat, patients)
 }
@@ -246,7 +246,7 @@ extract_observed_values <- function(object) {
     assert_class(object, "DataJoint")
     data <- as.list(object)
     x <- data.frame(
-        subject = names(data$pt_to_ind)[data$subject_tumour_index],
+        subject = names(data$subject_to_index)[data$subject_tumour_index],
         time = data$tumour_time,
         Yob = data$tumour_value
     )
diff --git a/R/DataSubject.R b/R/DataSubject.R
index 3d83df4c..25e61603 100644
--- a/R/DataSubject.R
+++ b/R/DataSubject.R
@@ -111,7 +111,7 @@ as_stan_list.DataSubject <- function(object, ...) {
         n_arms = length(unique(df[[vars$arm]])),
         subject_study_index = as.numeric(df[[vars$study]]),
         subject_arm_index = as.numeric(df[[vars$arm]]),
-        pt_to_ind = stats::setNames(
+        subject_to_index = stats::setNames(
             seq_len(nlevels(df[[vars$subject]])),
             levels(df[[vars$subject]])
         )
diff --git a/R/Grid.R b/R/Grid.R
index fa5abcf9..2aa48a48 100644
--- a/R/Grid.R
+++ b/R/Grid.R
@@ -7,11 +7,30 @@
 #' If `NULL` will default to 201 evenly spaced timepoints between 0 and either the max
 #' observation time (for [`LongitudinalQuantities`]) or max event time (for [`SurvivalQuantities`]).
 #' @param groups (`list`)\cr named list of subjects to extract quantities for. See Group Specification.
-#'
+#' @param spec (`list`)\cr named list of subjects to extract quantities for. The names of each
+#' element should be the required subjects with the element itself being a numeric vector of timepoints
+#' to generate the quantity at.
+#' @param length.out (`numeric`)\cr number of evenly spaced timepoints to generate quantities at.
 #' @description
 #' These functions are used to specify which subjects and timepoints should be generated
 #' when calculating quantities via [`SurvivalQuantities`] and [`LongitudinalQuantities`].
 #'
+#' @details
+#'
+#' - `GridFixed()` is used to specify a fixed set of timepoints to generate quantities at for
+#' all the specified subjects.
+#'
+#' - `GridGrouped()` is similar to `GridFixed()` but allows for groupwise averaging
+#' (see Group Specification).
+#'
+#' - `GridObserved()` generates quantities at the observed longitudinal timepoints for each
+#' subject.
+#'
+#' - `GridManual()` allows for individual timepoint specification for each subject.
+#'
+#' - `GridEven()` generates quantities for each subject at N evenly spaced timepoints
+#' between each subjects first and last longitudinal observations.
+#'
 #' @section Group Specification:
 #' For `GridGrouped()`, `groups` must be a named list of character vectors. Each element of the list
 #' must be a character vector of the subjects that will form the group where the element name
@@ -163,3 +182,37 @@ setValidity(
 length.QuantityCollapser <- function(x) {
     length(x@indexes)
 }
+
+
+#' Expand and Validate Subjects
+#'
+#' @param subjects (`character`)\cr vector of subjects that should exist in `data`
+#' @param data (`DataJoint`)\cr Survival and Longitudinal Data.
+#'
+#' @description
+#' If `subjects` is `NULL` this will return a named list of all subjects in `data`.
+#' Else it will return `subjects` as a named list ensuring that all subjects exist in `data`.
+#'
+#' @keywords internal
+subjects_to_list <- function(subjects = NULL, data) {
+    data_list <- as.list(data)
+    subjects_exp <- if (is.null(subjects)) {
+        subs <- as.list(names(data_list$subject_to_index))
+        names(subs) <- names(data_list$subject_to_index)
+        subs
+    } else {
+        subs <- as.list(subjects)
+        names(subs) <- subjects
+        subs
+    }
+    subjects_exp_vec <- unlist(subjects_exp, use.names = FALSE)
+    assert_that(
+        identical(subjects_exp_vec, unique(subjects_exp_vec)),
+        msg = "All subject names must be unique"
+    )
+    assert_that(
+        all(subjects_exp_vec %in% names(data_list$subject_to_index)),
+        msg = "Not all subjects exist within the data object"
+    )
+    subjects_exp
+}
diff --git a/R/GridEven.R b/R/GridEven.R
new file mode 100644
index 00000000..24f8b4ec
--- /dev/null
+++ b/R/GridEven.R
@@ -0,0 +1,82 @@
+
+#' @include Grid.R
+#' @include generics.R
+NULL
+
+
+#' @rdname Grid-Dev
+.GridEven <- setClass(
+    "GridEven",
+    contains = "Grid",
+    slots = c(
+        "subjects" = "character",
+        "length.out" = "numeric"
+    )
+)
+
+
+#' @rdname Grid-Functions
+#' @export
+GridEven <- function(subjects = NULL, length.out = 30) {
+    .GridEven(
+        subjects = subjects,
+        length.out = length.out
+    )
+}
+
+
+setValidity(
+    "GridEven",
+    function(object) {
+        if (length(object@length.out) != 1 || all(object@length.out <= 0)) {
+            return("The `length.out` argument must be a positive integer")
+        }
+    }
+)
+
+
+#' @rdname Quant-Dev
+#' @export
+as.QuantityGenerator.GridEven <- function(object, data, ...) {
+    assert_class(data, "DataJoint")
+    data_list <- as.list(data)
+    subjects <- unlist(as.list(object, data = data), use.names = FALSE)
+    assert_that(
+        all(subjects %in% names(data_list$subject_to_index)),
+        msg = "All subject names must be in the `DataSubject` object"
+    )
+
+    spec <- lapply(
+        subjects,
+        \(sub) {
+            subject_index <- data_list$subject_to_index[[sub]]
+            time_index <- data_list$subject_tumour_index == subject_index
+            subject_times <- data_list$tumour_time[time_index]
+            seq(min(subject_times), max(subject_times), length.out = object@length.out)
+        }
+    )
+    names(spec) <- subjects
+
+    as.QuantityGenerator(
+        GridManual(spec),
+        data = data
+    )
+}
+
+
+#' @rdname Quant-Dev
+#' @export
+as.QuantityCollapser.GridEven <- function(object, data, ...) {
+    generator <- as.QuantityGenerator(object, data)
+    QuantityCollapser(
+        times = generator@times,
+        groups = generator@subjects,
+        indexes = as.list(seq_along(generator@times))
+    )
+}
+
+
+#' @export
+as.list.GridEven <- function(x, data, ...) {
+    subjects_to_list(x@subjects, data)
+}
diff --git a/R/GridFixed.R b/R/GridFixed.R
index 6dc1bd85..b7f21c0a 100644
--- a/R/GridFixed.R
+++ b/R/GridFixed.R
@@ -56,21 +56,5 @@ as.QuantityCollapser.GridFixed <- function(object, data, ...) {
 
 #' @export
 as.list.GridFixed <- function(x, data, ...) {
-    data_list <- as.list(data)
-    subjects <- if (is.null(x@subjects)) {
-        subs <- as.list(names(data_list$pt_to_ind))
-        names(subs) <- names(data_list$pt_to_ind)
-        subs
-    } else {
-        subs <- as.list(x@subjects)
-        names(subs) <- x@subjects
-        subs
-    }
-    assert_that(
-        identical(
-            unlist(subjects, use.names = FALSE),
-            unique(unlist(subjects, use.names = FALSE))
-        )
-    )
-    subjects
+    subjects_to_list(x@subjects, data)
 }
diff --git a/R/GridGrouped.R b/R/GridGrouped.R
index 6678bd62..625d44d9 100644
--- a/R/GridGrouped.R
+++ b/R/GridGrouped.R
@@ -46,7 +46,7 @@ as.QuantityGenerator.GridGrouped <- function(object, data, ...) {
     data_list <- as.list(data)
     patients_unique <- unique(unlist(object@groups))
     assert_that(
-        all(patients_unique %in% names(data_list$pt_to_ind))
+        all(patients_unique %in% names(data_list$subject_to_index))
     )
     as.QuantityGenerator(
         GridFixed(
@@ -64,7 +64,7 @@ as.QuantityCollapser.GridGrouped <- function(object, data, ...) {
     assert_class(data, "DataJoint")
     data_list <- as.list(data)
     assert_that(
-        all(unique(unlist(object@groups)) %in% names(data_list$pt_to_ind))
+        all(unique(unlist(object@groups)) %in% names(data_list$subject_to_index))
     )
     time_grid <- expand_time_grid(object@times, max(data_list[["tumour_time"]]))
 
diff --git a/R/GridManual.R b/R/GridManual.R
new file mode 100644
index 00000000..1fa2b6e1
--- /dev/null
+++ b/R/GridManual.R
@@ -0,0 +1,81 @@
+
+#' @include Grid.R
+#' @include generics.R
+NULL
+
+
+#' @rdname Grid-Dev
+.GridManual <- setClass(
+    "GridManual",
+    contains = "Grid",
+    slots = c(
+        "spec" = "list"
+    )
+)
+
+
+#' @rdname Grid-Functions
+#' @export
+GridManual <- function(spec) {
+    .GridManual(
+        spec = spec
+    )
+}
+
+
+setValidity(
+    "GridManual",
+    function(object) {
+        subject_names <- names(object@spec)
+        subject_names_valid <- subject_names[!is.na(subject_names) & subject_names != ""]
+        if (length(subject_names_valid) != length(object@spec)) {
+            return("Each element of `subjects` must be named")
+        }
+        for (times in object@spec) {
+            if (!is.numeric(times)) {
+                return("Each element of `spec` must be a numeric vector")
+            }
+            if (length(times) != length(unique(times))) {
+                return("Each time vector per subject must be unique")
+            }
+        }
+        return(TRUE)
+    }
+)
+
+
+#' @rdname Quant-Dev
+#' @export
+as.QuantityGenerator.GridManual <- function(object, data, ...) {
+    assert_class(data, "DataJoint")
+    data_list <- as.list(data)
+    assert_that(
+        all(names(object@spec) %in% names(data_list$subject_to_index)),
+        msg = "All subject names must be in the `DataSubject` object"
+    )
+    lens <- vapply(object@spec, length, numeric(1))
+    .QuantityGenerator(
+        times = unlist(object@spec, use.names = FALSE),
+        subjects = rep(names(object@spec), lens)
+    )
+}
+
+
+#' @rdname Quant-Dev
+#' @export
+as.QuantityCollapser.GridManual <- function(object, data, ...) {
+    generator <- as.QuantityGenerator(object, data)
+    QuantityCollapser(
+        times = generator@times,
+        groups = generator@subjects,
+        indexes = as.list(seq_along(generator@times))
+    )
+}
+
+
+#' @export
+as.list.GridManual <- function(x, data, ...) {
+    subs <- as.list(names(x@spec))
+    names(subs) <- names(x@spec)
+    subs
+}
diff --git a/R/GridObserved.R b/R/GridObserved.R
index be1bad9b..21ffade8 100644
--- a/R/GridObserved.R
+++ b/R/GridObserved.R
@@ -27,7 +27,7 @@ as.QuantityGenerator.GridObserved <- function(object, data, ...) {
     data_list <- as.list(data)
     subjects <- unlist(as.list(object, data = data), use.names = FALSE)
     unique_visits <- tapply(data_list$tumour_time, data_list$subject_tumour_index, unique)
-    patient_visits <- unique_visits[data_list$pt_to_ind[subjects]]
+    patient_visits <- unique_visits[data_list$subject_to_index[subjects]]
     visit_lengths <- vapply(patient_visits, length, numeric(1))
     .QuantityGenerator(
         times = unlist(patient_visits, use.names = FALSE),
@@ -49,21 +49,5 @@ as.QuantityCollapser.GridObserved <- function(object, data, ...) {
 
 #' @export
 as.list.GridObserved <- function(x, data, ...) {
-    data_list <- as.list(data)
-    subjects <- if (is.null(x@subjects)) {
-        subs <- as.list(names(data_list$pt_to_ind))
-        names(subs) <- names(data_list$pt_to_ind)
-        subs
-    } else {
-        subs <- as.list(x@subjects)
-        names(subs) <- x@subjects
-        subs
-    }
-    assert_that(
-        identical(
-            unlist(subjects, use.names = FALSE),
-            unique(unlist(subjects, use.names = FALSE))
-        )
-    )
-    subjects
+    subjects_to_list(x@subjects, data)
 }
diff --git a/R/JointModelSamples.R b/R/JointModelSamples.R
index 75e5f58e..bb0fb28c 100644
--- a/R/JointModelSamples.R
+++ b/R/JointModelSamples.R
@@ -46,7 +46,7 @@ generateQuantities.JointModelSamples <- function(object, generator, type, ...) {
         length(type) == 1,
         type %in% c("survival", "longitudinal"),
         length(patients) == length(times),
-        all(patients %in% names(data$pt_to_ind))
+        all(patients %in% names(data$subject_to_index))
     )
 
     if (type == "survival") {
@@ -58,7 +58,7 @@ generateQuantities.JointModelSamples <- function(object, generator, type, ...) {
     }
 
     data[["gq_n_quant"]] <- length(patients)
-    data[["gq_pt_index"]] <- data$pt_to_ind[as.character(patients)]
+    data[["gq_pt_index"]] <- data$subject_to_index[as.character(patients)]
     data[["gq_times"]] <- times
 
     stanObject <- object@model@stan
diff --git a/inst/WORDLIST b/inst/WORDLIST
index dfb3f543..8790762f 100644
--- a/inst/WORDLIST
+++ b/inst/WORDLIST
@@ -137,3 +137,4 @@ SimLongitudinal
 SimSurvival
 geq
 LLoQ
+groupwise
diff --git a/man/Grid-Dev.Rd b/man/Grid-Dev.Rd
index ef009e10..aa5c69b6 100644
--- a/man/Grid-Dev.Rd
+++ b/man/Grid-Dev.Rd
@@ -1,15 +1,19 @@
 % Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/Grid.R, R/GridFixed.R, R/GridGrouped.R,
-%   R/GridObserved.R
+% Please edit documentation in R/Grid.R, R/GridEven.R, R/GridFixed.R,
+%   R/GridGrouped.R, R/GridManual.R, R/GridObserved.R
 \docType{class}
 \name{Grid-Dev}
 \alias{Grid-Dev}
 \alias{Grid-class}
 \alias{.Grid}
+\alias{GridEven-class}
+\alias{.GridEven}
 \alias{GridFixed-class}
 \alias{.GridFixed}
 \alias{GridGrouped-class}
 \alias{.GridGrouped}
+\alias{GridManual-class}
+\alias{.GridManual}
 \alias{GridObserved-class}
 \alias{.GridObserved}
 \title{Grid Developer Notes}
diff --git a/man/Grid-Functions.Rd b/man/Grid-Functions.Rd
index 0f4e97b5..a89d1371 100644
--- a/man/Grid-Functions.Rd
+++ b/man/Grid-Functions.Rd
@@ -1,33 +1,58 @@
 % Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/Grid.R, R/GridFixed.R, R/GridGrouped.R,
-%   R/GridObserved.R
+% Please edit documentation in R/Grid.R, R/GridEven.R, R/GridFixed.R,
+%   R/GridGrouped.R, R/GridManual.R, R/GridObserved.R
 \name{Grid-Functions}
 \alias{Grid-Functions}
+\alias{GridEven}
 \alias{GridFixed}
 \alias{GridGrouped}
+\alias{GridManual}
 \alias{GridObserved}
 \title{Quantity Grid Specification}
 \usage{
+GridEven(subjects = NULL, length.out = 30)
+
 GridFixed(subjects = NULL, times = NULL)
 
 GridGrouped(groups, times = NULL)
 
+GridManual(spec)
+
 GridObserved(subjects = NULL)
 }
 \arguments{
 \item{subjects}{(\code{character} or \code{NULL})\cr vector of subjects to extract quantities for.
 If \code{NULL} will default to all subjects within the dataset.}
 
+\item{length.out}{(\code{numeric})\cr number of evenly spaced timepoints to generate quantities at.}
+
 \item{times}{(\code{numeric} or \code{NULL})\cr vector of time points to extract quantities at.
 If \code{NULL} will default to 201 evenly spaced timepoints between 0 and either the max
 observation time (for \code{\link{LongitudinalQuantities}}) or max event time (for \code{\link{SurvivalQuantities}}).}
 
 \item{groups}{(\code{list})\cr named list of subjects to extract quantities for. See Group Specification.}
+
+\item{spec}{(\code{list})\cr named list of subjects to extract quantities for. The names of each
+element should be the required subjects with the element itself being a numeric vector of timepoints
+to generate the quantity at.}
 }
 \description{
 These functions are used to specify which subjects and timepoints should be generated
 when calculating quantities via \code{\link{SurvivalQuantities}} and \code{\link{LongitudinalQuantities}}.
 }
+\details{
+\itemize{
+\item \code{GridFixed()} is used to specify a fixed set of timepoints to generate quantities at for
+all the specified subjects.
+\item \code{GridGrouped()} is similar to \code{GridFixed()} but allows for groupwise averaging
+(see Group Specification).
+\item \code{GridObserved()} generates quantities at the observed longitudinal timepoints for each
+subject.
+\item \code{GridManual()} allows for individual timepoint specification for each subject.
+\item \code{GridEven()} generates quantities for each subject at N evenly spaced timepoints
+between each subjects first and last longitudinal observations.
+}
+}
 \section{Group Specification}{
 
 For \code{GridGrouped()}, \code{groups} must be a named list of character vectors. Each element of the list
diff --git a/man/Quant-Dev.Rd b/man/Quant-Dev.Rd
index 5a30c1ce..3c3e493b 100644
--- a/man/Quant-Dev.Rd
+++ b/man/Quant-Dev.Rd
@@ -1,6 +1,6 @@
 % Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/generics.R, R/Grid.R, R/GridFixed.R,
-%   R/GridGrouped.R, R/GridObserved.R
+% Please edit documentation in R/generics.R, R/Grid.R, R/GridEven.R,
+%   R/GridFixed.R, R/GridGrouped.R, R/GridManual.R, R/GridObserved.R
 \docType{class}
 \name{as.QuantityGenerator}
 \alias{as.QuantityGenerator}
@@ -12,10 +12,14 @@
 \alias{QuantityCollapser-class}
 \alias{.QuantityCollapser}
 \alias{QuantityCollapser}
+\alias{as.QuantityGenerator.GridEven}
+\alias{as.QuantityCollapser.GridEven}
 \alias{as.QuantityGenerator.GridFixed}
 \alias{as.QuantityCollapser.GridFixed}
 \alias{as.QuantityGenerator.GridGrouped}
 \alias{as.QuantityCollapser.GridGrouped}
+\alias{as.QuantityGenerator.GridManual}
+\alias{as.QuantityCollapser.GridManual}
 \alias{as.QuantityGenerator.GridObserved}
 \alias{as.QuantityCollapser.GridObserved}
 \title{Quantity Developer Notes}
@@ -28,6 +32,10 @@ QuantityGenerator(times, subjects)
 
 QuantityCollapser(times, groups, indexes)
 
+\method{as.QuantityGenerator}{GridEven}(object, data, ...)
+
+\method{as.QuantityCollapser}{GridEven}(object, data, ...)
+
 \method{as.QuantityGenerator}{GridFixed}(object, data, ...)
 
 \method{as.QuantityCollapser}{GridFixed}(object, data, ...)
@@ -36,6 +44,10 @@ QuantityCollapser(times, groups, indexes)
 
 \method{as.QuantityCollapser}{GridGrouped}(object, data, ...)
 
+\method{as.QuantityGenerator}{GridManual}(object, data, ...)
+
+\method{as.QuantityCollapser}{GridManual}(object, data, ...)
+
 \method{as.QuantityGenerator}{GridObserved}(object, data, ...)
 
 \method{as.QuantityCollapser}{GridObserved}(object, data, ...)
diff --git a/tests/testthat/test-DataJoint.R b/tests/testthat/test-DataJoint.R
index 8312d87d..d53b1fdc 100644
--- a/tests/testthat/test-DataJoint.R
+++ b/tests/testthat/test-DataJoint.R
@@ -38,7 +38,7 @@ test_that("DataJoint basic usage", {
     li <- as.list(d_joint)
     expect_equal(li$n_subjects, 3)
     expect_equal(li$n_tumour_all, 6)
-    expect_equal(li$pt_to_ind, c("C" = 1, "B" = 2, "A" = 3))
+    expect_equal(li$subject_to_index, c("C" = 1, "B" = 2, "A" = 3))
     expect_equal(li$n_arms, 3)
     expect_equal(li$subject_study_index, c(2, 1, 1))
     expect_equal(li$n_studies, 2)
diff --git a/tests/testthat/test-DataSubject.R b/tests/testthat/test-DataSubject.R
index 6b0f9413..807eb62b 100644
--- a/tests/testthat/test-DataSubject.R
+++ b/tests/testthat/test-DataSubject.R
@@ -20,7 +20,7 @@ test_that("DataSubject works as expected", {
 
     expected_variables <- c(
         "n_subjects", "n_studies", "n_arms", "subject_study_index",
-        "subject_arm_index", "pt_to_ind"
+        "subject_arm_index", "subject_to_index"
     )
 
     li <- as_stan_list(obj)
@@ -32,7 +32,7 @@ test_that("DataSubject works as expected", {
     expect_equal(li$n_arms, 3)
     expect_equal(li$subject_study_index, c(2, 1, 1, 2))
     expect_equal(li$subject_arm_index, c(3, 2, 1, 3))
-    expect_equal(li$pt_to_ind, c("C" = 1, "B" = 2, "A" = 3, "D" = 4))
+    expect_equal(li$subject_to_index, c("C" = 1, "B" = 2, "A" = 3, "D" = 4))
 })
 
 test_that("DataSubject print method works as expected", {
diff --git a/tests/testthat/test-Grid.R b/tests/testthat/test-Grid.R
index 61740b6b..370aa236 100644
--- a/tests/testthat/test-Grid.R
+++ b/tests/testthat/test-Grid.R
@@ -105,6 +105,59 @@ test_that("Grid objects work with QuantityGenerator and QuantityCollapser", {
     )
     expect_equal(actual, expected)
 
+
+    #
+    # GridManual
+    #
+    grid <- GridManual(
+        spec = list(
+            "B" = c(2, 4),
+            "A" = c(1, 10, 50),
+            "C" = 6
+        )
+    )
+    actual <- as.QuantityGenerator(grid, data = dj)
+    expected <- .QuantityGenerator(
+        subjects = c("B", "B", "A", "A", "A", "C"),
+        times = c(2, 4, 1, 10, 50, 6)
+    )
+    expect_equal(actual, expected)
+
+    actual <- as.QuantityCollapser(grid, data = dj)
+    expected <- .QuantityCollapser(
+        groups = c("B", "B", "A", "A", "A", "C"),
+        times = c(2, 4, 1, 10, 50, 6),
+        indexes = list(1, 2, 3, 4, 5, 6)
+    )
+    expect_equal(actual, expected)
+
+
+
+    #
+    # GridEven
+    #
+    grid <- GridEven(
+        subjects = c("D", "A"),
+        length.out = 4
+    )
+    actual <- as.QuantityGenerator(grid, data = dj)
+    expected <- .QuantityGenerator(
+        subjects = c("D", "D", "D", "D", "A", "A", "A", "A"),
+        times = c(
+            seq(1000, 3000, length.out = 4),
+            seq(1, 3, length.out = 4)
+        )
+    )
+    expect_equal(actual, expected)
+
+    actual <- as.QuantityCollapser(grid, data = dj)
+    expected <- .QuantityCollapser(
+        groups = expected@subjects,
+        times = expected@times,
+        indexes = as.list(seq_along(expected@times))
+    )
+    expect_equal(actual, expected)
+
 })
 
 
@@ -218,14 +271,28 @@ test_that("GridObservered + Constructs correct quantities", {
     # Longitudinal Data
     #
     #
-    longquant <- LongitudinalQuantities(
+    longquant_obsv <- LongitudinalQuantities(
         mp,
         grid = GridObserved(
             subjects = c("pt_004", "pt_002", "pt_050")
         )
     )
+    actual_obsv <- summary(longquant_obsv)
+
+
+    longquant_manual <- LongitudinalQuantities(
+        mp,
+        grid = GridManual(
+            spec = list(
+                "pt_004" = dat_lm |> dplyr::filter(pt == "pt_004") |> dplyr::arrange(time) |> dplyr::pull(time),
+                "pt_002" = dat_lm |> dplyr::filter(pt == "pt_002") |> dplyr::arrange(time) |> dplyr::pull(time),
+                "pt_050" = dat_lm |> dplyr::filter(pt == "pt_050") |> dplyr::arrange(time) |> dplyr::pull(time)
+            )
+        )
+    )
+    actual_manual <- summary(longquant_manual)
 
-    actual <- summary(longquant)
+    expect_equal(actual_obsv, actual_manual)
 
 
     pred_mat <- as.CmdStanMCMC(mp)$draws("Ypred", format = "draws_matrix")
@@ -256,14 +323,11 @@ test_that("GridObservered + Constructs correct quantities", {
         upper = apply(preds_reduced, 2, quantile, 0.975)
     )
 
-    expect_gt(cor(actual$median, expected$median), 0.99999999)
-    expect_gt(cor(actual$lower, expected$lower), 0.99999999)
-    expect_gt(cor(actual$upper, expected$upper), 0.99999999)
-    expect_equal(actual$time, expected$time)
-    expect_equal(actual$group, expected$group)
-
-
-
+    expect_gt(cor(actual_obsv$median, expected$median), 0.99999999)
+    expect_gt(cor(actual_obsv$lower, expected$lower), 0.99999999)
+    expect_gt(cor(actual_obsv$upper, expected$upper), 0.99999999)
+    expect_equal(actual_obsv$time, expected$time)
+    expect_equal(actual_obsv$group, expected$group)
 
     #
     #
@@ -317,3 +381,38 @@ test_that("GridObservered + Constructs correct quantities", {
     expect_equal(actual$time, expected$time)
     expect_equal(actual$group, expected$pt)
 })
+
+
+test_that("subjects_to_list works as expected", {
+    df_subj <- data.frame(
+        vpt = factor(c("A", "B", "C"), levels = c("C", "B", "A")),
+        varm = c("A2", "A3", "A4"),
+        vstudy = c("S1", "S1", "S2")
+    )
+
+    d_joint <- DataJoint(
+        subject = DataSubject(
+            data = df_subj,
+            subject = "vpt",
+            arm = "varm",
+            study = "vstudy"
+        )
+    )
+
+    expect_equal(
+        subjects_to_list(NULL, data = d_joint),
+        list("C" = "C", "B" = "B", "A" = "A")
+    )
+    expect_equal(
+        subjects_to_list(c("A", "B"), data = d_joint),
+        list("A" = "A", "B" = "B")
+    )
+    expect_equal(
+        subjects_to_list(c("B"), data = d_joint),
+        list("B" = "B")
+    )
+    expect_error(
+        subjects_to_list(c("B", "XX"), data = d_joint),
+        regex = "Not all subjects exist within the data object"
+    )
+})