The Debian-Live approach also provides some good opportunities. First and foremost, the very easy remastering makes it efficient to run with no persistent store quite often. For instance, upon remastering, I just start without the store, and the image I run is union-mounted with the persistence file and copied&compressed. Then I have to boot something else to copy the new squashfs image in place, but that's all that has to be done outside the system.
Boot the new image without persistence, create a new persistence file.
For further adaptations, the new persistence file can be mounted in an instance run under kvm, programs can be added and settings tweaked for an eventual new remastering.
Storing the series of squashfs-compressed images, one can always go back in this process if needed.
Seagate ST8000NM0055 8TB 7200RPM 256MB SATA 6.0 Gb/s 3.5" Enterprise Hard Drive
$41.59
HITACHI HUS724040ALA640 4TB 7200RPM 64MB SATA 6.0Gb/s 3.5" HARD DRIVE ZERO HOURS
$52.00
Western Digital WD4000FYYZ RE 4TB 7200 RPM 64MB Cache SATA 6Gb/s 3.5" Hard Drive
$24.08
WD 5TB Certified Refurbished Elements, External Hard Drive - RWDBU6Y0050BBK-WESN
$78.99
HGST Ultrastar DC HC520 12TB SATA 6Gb 256MB 3.5" Enterprise HDD- HUH721212ALE601
$82.99
HGST Ultrastar HE10 10TB SATA 6.0Gb/s 7200 3.5" Datacenter HDD - HUH721010ALE601
$79.99
Seagate ST12000NM0127 12TB 256MB 7200RPM 3.5" SATA 6.0Gb/s Enterprise Hard Drive
$87.99
WD Ultrastar DC HC530 14TB SATA 6G 3.5" 7200RPM Enterprise HDD - WUH721414ALE604
$110.00
Seagate ST12000NM0127 12TB SATA 6Gb/s 256MB 7200RPM 3.5" Enterprise Hard Drive
$99.99
Seagate ST8000NM0045 8TB 7.2k SATA 6Gbps 3.5" 4Kn Format Hard Drive Open Box New
$84.99