Volumio Premium vs. Virtuoso

I hope this is the correct part of the forum for this - if not, please tell me so.
I have the old Virtuoso subscription and consider upgrading to Premium.
If I do so, will it be the same user name for all devices, it is used for?
If I wish to set up the devices differently, can these settings be backed up individually, so they can be restored?

Hi, I’m also on virtuoso.

Rather than start another thread, I was wondering if it’s possible to download your own library content for offline playback (eg outside the house when not on the same wi-fi network?

Is that what Automatic Sync of Personal items Remote connection to up to 6 devices means?