Support Doc for Database Cache Size (MB)?

No, because the script uses the SQLite executable which is included with your Plex server. New Plex server version, new SQLite executable.

What kind of DB Cache size would the smarter-than-me-people recommend for a server with 64GIG of ram, 3.000 movies, 70.000 episodes and 150.000 tracks?

I was trying to figure this out myself when the db size feature was introduced and even set it to 10+GB, but after I was receiving memory errors in the Plex web app (Chrome) I’ve shrunk it to 2GB.

Still I don’t have any idea of what would be an ideal value