Yes it uses the drive space left after the install ...... less any files you may have added afterwards, either by saving files or saving changes.
I don't understand this bit. Clearly, I still have 16GiB of space on my / partition so shouldn't the live session also be using that?
No, you have 16GB space on the partition, but that is not your / when running live.
Live systems use a virtual disk/ram disk, which is why you can load the live OS into RAM using the Copy2RAM option, and run it without any drive being present, or run it from a CD etc.
I think this is where the confusion is coming in.
The output of your 'df' command shows your / as a 1GB ram disk.
Issue a 'mount' command to see it a bit more clearly ...
/dev/root on / type rootfs (rw)
I would have to check, but the size of the RAM disk is defined in one of the mylivecd config files IIRC. Whether it is feasible or not to make changes there for your purposes I am unsure as I never tried it.
As you have shown, the changes can be written to any suitable location.
title PCLinuxOS 32-bit Packaging Environment
kernel (hd0,4)/pcliveos/32pack-isolinux/vmlinuz livecd=/pcliveos/32pack fromusb root=LABEL=/pcLiveos quiet fstab=rw,noauto acpi=on resume=LABEL=/pcliveos splash=silent vga=788 changes_dev=UUID=935585fa-8d39-428f-b7c8-f6d7f75e8adb
The above boot stanza does not appear to be one generated by the LiveUSB Creator, which does not use 'LABEL' but instead uses UUID. The latest also includes the 'quiet' boot option. That is just a comment, nothing more
It would appear that because of the default limitation of the size of the ram disk being used as / that this scheme may not be the most suitable for your purposes.
Have you tried mounting a Swap partition while running live ..... maybe a Swap from one of the internal HDDs? Use the command
(in my case swapon /dev/sda8 mounts the swap partition)
That should effectively give you more memory available when running live and might only come into use when packaging a large app.
Again I have to say this is something I have not had cause to investigate.
Regarding the questions that require answering when booting .... I seem to recall a discussion on that .... posted in the forum. ..... memory problems again ....
I dunno if I have addressed all you asked ..... but if not please post again
Some of your questions could be better answered by others also, so maybe they will drop by.