[Swiss1000]

I can certainly look into adding an option to keep login information separate per library. It would be disabled by default as that could be annoying for users with multiple libraries but only a single account. The other things are planned and should be addressed soon.

Sorry I wasn't attentiv to this : " MSP remembering which google drive account is linked to which library "

This is absurd from a computer and security perspective: the directory should be backed up by the directory, or shared directory, not the account. 

Everyone has their own Drive account, or whatever, and it's personal. A main account (Drive) includes a "Shared Directory."  This gives access to a directory containing files from other accounts, shared by the owners of those accounts. It's universal and logical. You think of these shares as personal folders, but they're temporary; the owner remains the owner.

If you remember the destination, as long as it's shared, you can write to it.

Let's take an example: Jazzy Boomers and Bowling Blues are two bands. Each has a directory for sheet music and shared files. 
Each musician has their own personal Drive account. 

If you have a new musician, you can provide them with a link or a shared part, depending on the band they belong to. 

When the musician leaves the band, you remove his access (adress) to the shared directory.
If the account is shared, they will have and keep full access, which you can't simply remove. 
This isn't what you want, and you have to change the password to remove access, which affects everyone have the same strategy and account memorized... 

You don't need to go beyond network logic to satisfy every request. You need to remember the access path only, in speparate librairy, and the PERSONAL account information, in global parameters.

I am campaigning for Mobilesheets to become a more effective tool for conducting, and we need to be careful about that.