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.
Dell PowerEdge R640 Server 2x Gold 6150 2.70Ghz 36-Core 256GB 2x 960GB SSD H730P
$1737.25
Dell PowerEdge R730 Server 2.30Ghz 32-Core 128GB 8x 3TB 12G H730P ESXi 7.0
$935.50
Dell PowerEdge R730xd Server 2x E5-2699v4 2.20Ghz 44-Core 256GB H730P
$1096.95
Dell R740XD 24SFF 12 NVMe 2.9Ghz 48-C 256GB H730P 2x10G+2x1G NIC 2x1100W Rails
$6332.07
Dell PowerEdge R720XD Xeon E5-2680 V2 2.8GHz 20 Cores 256GB RAM 12x4TB
$510.00
DELL PowerEdge R730 Server 2x E5-2690v3 2.6GHz =24 Cores 32GB H730 4xRJ45
$275.00
Dell PowerEdge R730XD 28 Core Server 2X Xeon E5-2680 V4 H730 128GB RAM No HDD
$389.99
Dell PowerEdge R720 Server - 2x8c CPU,256Gb RAM, 128Gb SSD/3x600Gb SAS, Proxmox
$340.00
Dell PowerEdge R430 3.5 1U 2x E5-2690 v3 2.6ghz 24-Cores 256gb 4x Trays 2x 550w
$289.99
Dell PowerEdge R820 Server 4x E5-4620 2.2GHz 32-Core Total 256GB 0HD 2x 1100w
$315.00