The individual settings in the .rvedb file are not documented, but the general usage of the file is discussing in the Calibre Interactive and Calibre RVE User's Manual.
Where is the .rvedb file you are looking at located? In typical usage, the file is updated with current settings each time you exit RVE and the file is saved in your home directory. The environment variable MGC_RVEDB_DIR can be used to set a different location for the .rvedb file.
So, for example, if you open Calibre RVE, change the window size, exit RVE, then open RVE again, you should see the new window size. If you don't, make sure the location where .rvedb is stored has write permission.
Hope that helps,
Thanks. The .rvedb file looks to be the answer.
I am not yet able to get it to work, but I think it is particular to our company's implementation.