How do I backup snaps automatically?

How do I backup snaps automatically offsite?
My preferred backup provider is Restic. Would make cron execute this:
snap save && restic -r rclone:storage:snap-backup backup && snap forget 1234
This makes snapshots, backs them up and can’t forget

Is there any way to set the id, when saving? I can’t automatically forget the created snapshot without knowing the backup id (unless I keep track of that via a script).

An another problem is, that the snapshots are .zip files - no deduplication across backups. I could just as well use rclone copy to move the zip then.

My temporary solution currently is to backup /var/snap directory. Is that safe and intended?