Hi
AS regards this idea-> https://tails.boum.org/blueprint/backups/     -  
Backups of the persistent volume
I am a user (and donor)
Backups of the persistent volume is a bit of an issue and my suggestion
is as follows--
Applications> Tails Installer has options of:-
1    Clone                                (other partitions lost)
2    Clone & Upgrade            (other partitions like Persistent volume
on the target retained)
3    Install TAILS from an iso.
What about an option  'Clone Everything'   - so the original TAILS _and_
the Persistent volume on the original are cloned to the target. - that
is the backup.
Regards
Lawrie