diff --git a/src/composables/useSettings.ts b/src/composables/useSettings.ts
index 042de79..c310d4b 100644
--- a/src/composables/useSettings.ts
+++ b/src/composables/useSettings.ts
@@ -166,9 +166,9 @@ export const get_global_pmtiles_url = (year: number) => {
 }
 
 export const AREA_OVERVIEW_COG =
-  'https://s3.us-west-2.amazonaws.com/us-west-2.opendata.source.coop/m-mohr/ftw-confidence-layers/prue_v1_field_area_500m_fieldsonly.tif'
+  'https://s3.us-west-2.amazonaws.com/us-west-2.opendata.source.coop/m-mohr/ftw-confidence-layers/prue_v1_field_area_500m_fieldsonly_uint8_3857.tif'
 export const CONFIDENCE_OVERVIEW_COG =
-  'https://s3.us-west-2.amazonaws.com/us-west-2.opendata.source.coop/m-mohr/ftw-confidence-layers/prue_v1_confidence_global.tif'
+  'https://s3.us-west-2.amazonaws.com/us-west-2.opendata.source.coop/m-mohr/ftw-confidence-layers/prue_v1_confidence_global_uint8_3857.tif'
 
 export default function useSettings() {
   return {
diff --git a/src/layers/Global-Overview-Layers.ts b/src/layers/Global-Overview-Layers.ts
index bd0e169..da4cf62 100644
--- a/src/layers/Global-Overview-Layers.ts
+++ b/src/layers/Global-Overview-Layers.ts
@@ -38,12 +38,16 @@ export const createGlobalOverviewLayer = (settings: Settings) => {
     source: new GeoTIFF({
       sources: [
         {
-          // todo: try https://tiles.rdnt.io/tiles/{z}/{x}/{y}@2x?url=
           url: settings.aggregate === 'confidence' ? CONFIDENCE_OVERVIEW_COG : AREA_OVERVIEW_COG,
+          nodata: 255,
           min: 0,
-          max: settings.aggregate === 'confidence' ? 1 : 2500,
+          max: 200,
         },
       ],
+      interpolate: false,
+      sourceOptions: {
+        blockSize: 512 * 1024, // 512KB: capture all IFDs in 1-2 requests instead of 100+
+      },
     }),
     minZoom: 0,
     maxZoom: GLOBAL_DATA_MAP_FIELD_START_ZOOM_LEVEL,