diff --git a/modules/dashboard/sections/collapsible/main.tf b/modules/dashboard/sections/collapsible/main.tf
index 874ae2d4..c5429cae 100644
--- a/modules/dashboard/sections/collapsible/main.tf
+++ b/modules/dashboard/sections/collapsible/main.tf
@@ -1,6 +1,6 @@
 variable "title" { type = string }
 variable "tiles" {}
-variable "collapsed" { default = false }
+variable "collapsed" { type = optional(bool) }
 
 locals {
   start_row = length(var.tiles) == 0 ? 0 : min([for s in var.tiles : s.yPos]...)
@@ -10,14 +10,14 @@ module "width" { source = "../width" }
 
 output "section" {
   value = concat([{
-    yPos   = local.start_row
-    xPos   = 0,
+    yPos   = local.start_row != 0 ? local.start_row : null,
+    xPos   = null,
     height = length(var.tiles) == 0 ? 0 : max([for s in var.tiles : s.yPos + s.height - local.start_row]...),
     width  = module.width.size,
     widget = {
       title = var.title
       collapsibleGroup = {
-        collapsed = var.collapsed
+        collapsed = var.collapsed ? true : null
       }
     },
   }], var.tiles)
diff --git a/modules/dashboard/sections/layout/main.tf b/modules/dashboard/sections/layout/main.tf
index bc0f045e..317dc65b 100644
--- a/modules/dashboard/sections/layout/main.tf
+++ b/modules/dashboard/sections/layout/main.tf
@@ -14,8 +14,8 @@ locals {
   // the section, which starts after the topmost tile of the preceding section.
   rebased = [for s in var.sections : [
     for t in s : {
-      yPos   = t.yPos + local.sum_heights[index(var.sections, s)]
-      xPos   = t.xPos
+      yPos   = t.yPos + local.sum_heights[index(var.sections, s)] != 0 ? t.yPos + local.sum_heights[index(var.sections, s)] : null
+      xPos   = t.xPos != 0 ? t.xPos : null
       height = t.height
       width  = t.width
       widget = t.widget
diff --git a/modules/dashboard/widgets/latency/main.tf b/modules/dashboard/widgets/latency/main.tf
index aeebabce..730f2c3f 100644
--- a/modules/dashboard/widgets/latency/main.tf
+++ b/modules/dashboard/widgets/latency/main.tf
@@ -1,5 +1,5 @@
 variable "title" { type = string }
-variable "group_by_fields" { default = [] }
+variable "group_by_fields" { type = list(string) }
 variable "filter" { type = list(string) }
 variable "band" {
   type    = number
diff --git a/modules/dashboard/widgets/xy-ratio/main.tf b/modules/dashboard/widgets/xy-ratio/main.tf
index f6ec31d2..6580e206 100644
--- a/modules/dashboard/widgets/xy-ratio/main.tf
+++ b/modules/dashboard/widgets/xy-ratio/main.tf
@@ -1,16 +1,21 @@
 variable "title" { type = string }
 variable "legend" { default = "" }
-variable "numerator_group_by_fields" { default = [] }
-variable "denominator_group_by_fields" { default = [] }
+variable "numerator_group_by_fields" { type = list(string) }
+variable "denominator_group_by_fields" { type = list(string) }
 variable "numerator_filter" { type = list(string) }
 variable "denominator_filter" { type = list(string) }
 variable "plot_type" { default = "LINE" }
 variable "alignment_period" { default = "60s" }
-variable "numerator_align" { default = "ALIGN_RATE" }
+variable "numerator_align" { type = optional(string) /* default: "ALIGN_RATE" */ }
 variable "numerator_reduce" { default = "REDUCE_SUM" }
-variable "denominator_align" { default = "ALIGN_RATE" }
+variable "denominator_align" { type = optional(string) /* default: "ALIGN_RATE" */ }
 variable "denominator_reduce" { default = "REDUCE_SUM" }
-variable "thresholds" { default = [] }
+variable "thresholds" { type = list(string) }
+
+locals {
+  default_align  = "ALIGN_RATE"
+  default_reduce = "REDUCE_NONE"
+}
 
 // https://cloud.google.com/monitoring/api/ref_v3/rest/v1/projects.dashboards#XyChart
 output "widget" {
@@ -30,18 +35,18 @@ output "widget" {
               filter = join("\n", var.numerator_filter)
               aggregation = {
                 alignmentPeriod    = var.alignment_period
-                perSeriesAligner   = var.numerator_align
-                crossSeriesReducer = var.numerator_reduce
-                groupByFields      = var.numerator_group_by_fields
+                perSeriesAligner   = var.numerator_align == local.default_align ? null : var.numerator_align
+                crossSeriesReducer = var.numerator_reduce == local.default_reduce ? null : var.numerator_reduce
+                groupByFields      = length(var.numerator_group_by_fields) == 0 ? null : var.numerator_group_by_fields
               }
             }
             denominator = {
               filter = join("\n", var.denominator_filter)
               aggregation = {
                 alignmentPeriod    = var.alignment_period
-                perSeriesAligner   = var.denominator_align
-                crossSeriesReducer = var.denominator_reduce
-                groupByFields      = var.denominator_group_by_fields
+                perSeriesAligner   = var.denominator_align == local.default_align ? null : var.denominator_align
+                crossSeriesReducer = var.denominator_reduce == local.default_reduce ? null : var.denominator_reduce
+                groupByFields      = length(var.denominator_group_by_fields)
               }
             }
           }
diff --git a/modules/dashboard/widgets/xy/main.tf b/modules/dashboard/widgets/xy/main.tf
index 4c7a40d6..4fffcb2e 100644
--- a/modules/dashboard/widgets/xy/main.tf
+++ b/modules/dashboard/widgets/xy/main.tf
@@ -1,12 +1,17 @@
 variable "title" { type = string }
-variable "group_by_fields" { default = [] }
+variable "group_by_fields" { type = list(string) }
 variable "filter" { type = list(string) }
 variable "plot_type" { default = "LINE" }
 variable "alignment_period" { default = "60s" }
-variable "primary_align" { default = "ALIGN_RATE" }
-variable "primary_reduce" { default = "REDUCE_NONE" }
-variable "secondary_align" { default = "ALIGN_NONE" }
-variable "secondary_reduce" { default = "REDUCE_NONE" }
+variable "primary_align" { type = optional(string) /* default: "ALIGN_RATE" */ }
+variable "primary_reduce" { type = optional(string) /* default:  "REDUCE_NONE" */ }
+variable "secondary_align" { type = optional(string) /* default: "ALIGN_NONE" */ }
+variable "secondary_reduce" { type = optional(string) /* default: "REDUCE_NONE" */ }
+
+locals {
+  default_align  = "ALIGN_RATE"
+  default_reduce = "REDUCE_NONE"
+}
 
 // https://cloud.google.com/monitoring/api/ref_v3/rest/v1/projects.dashboards#XyChart
 output "widget" {
@@ -22,16 +27,16 @@ output "widget" {
           timeSeriesFilter = {
             aggregation = {
               alignmentPeriod    = var.alignment_period
-              perSeriesAligner   = var.primary_align
-              crossSeriesReducer = var.primary_reduce
-              groupByFields      = var.group_by_fields
+              perSeriesAligner   = var.primary_align == local.default_align ? null : var.primary_align
+              crossSeriesReducer = var.primary_reduce == local.default_reduce ? null : var.primary_reduce
+              groupByFields      = length(var.group_by_fields) == 0 ? null : var.group_by_fields
             }
             filter = join("\n", var.filter)
             secondaryAggregation = {
               alignmentPeriod    = var.alignment_period
-              perSeriesAligner   = var.secondary_align
-              crossSeriesReducer = var.secondary_reduce
-              groupByFields      = var.group_by_fields
+              perSeriesAligner   = var.secondary_align == local.default_align ? null : var.secondary_align
+              crossSeriesReducer = var.secondary_reduce == local.default_reduce ? null : var.secondary_reduce
+              groupByFields      = length(var.group_by_fields) == 0 ? null : var.group_by_fields
             }
           }
         }