I want the two mixed together. During single sessions save (or not), periodically merge all of the saved stuff into the main filesystem. On a live running system.It's that simple, a binary choice: either remaster, or use persistence/save, but don't mix them together
Which means that once the merge save folder (partition) content is saved into the filesystem it can be deleted. The problem is removing that content in a live system as those files are being used at the time. For porteus boot I have it set so that the system reboots and the initrd detects a flag file and cleans out the save folder content before its used - and where that initrd is in effect locked (kernel updates are pinned to not happen). With boot 3 the initrd is in effect inaccessible as Debian could replace that (updates) with versions that wouldn't include that 'delete save folder content if flag file exists'.