I am currently creating an elevation image service for a large area which consists of 100% coverage of 25m SRTM and approx. 45% coverage of a mixed 1, 2 and 5 metre resolutions derived from stereo and LiDAR. I am creating 17 levels of cache using the ArcGIS Online Elevation schema. The full cache was built whilst only the 25m tiles were in the Mosaic dataset which built 13 levels of cache. After this the higher resolution tiles were added in 100K index blocks and the cache reprocessed using an AOI based on a dissolve of the footprints for the
