Cache-backend db consistency / best practices

I’m trying to use the cache (gdrive-cache-crypt if it matters) to avoid throttling and just because I’m nice (really). I don’t mount anything, I’m just doing sync from one machine and I’d like to keep a consistent and long-term cache of metadata. I have plenty of files (even if not large) and everything goes much faster from the cache, especially when there isn’t anything to sync. Are the following operations safe:

a. starting a second sync concurrently but syncing another folder (it’s on the same machine, same config/remote but different things to sync)?
b. just CTRL+C out of sync at some point (can it leave the db in some un-sane state)?

A is not possible. The cache backend locks the DB mapped to the remote (regardless of the root path) and no other process can access it.

B should be ok. Cache cleans up after it pretty well.