My apologies. I forgot to mention that the Cloud Storage I am using is Dropbox which supports block-level transfers. I use it to store several 1 GB encrypted volumes and Dropbox will sync them in seconds after changing a few files in local copies of the volumes. It is impracticable to use any of the other popular Cloud Storage services in this way because as you say even a small change in the content of a local copy of the volume requires re-uploading the entire 1 GB file.
For information, Dropbox can only sync the volumes when they are dismounted since their files are locked when mounted. I tested RaiDrive with a very small test volume but of course I was mounting the locally cached copy not one stored in the Cloud. My aim was to avoid keeping local copies by using RaiDrive to directly mount volumes stored on Dropbox. The only way to test whether that is possible would be to turn off RaiDrive caching.