I was looking at some of the posts about making a live USB and it seems that I have to have an iso file.
No, an ISO is definitely the most popular, but the utility can use the files such as are generated by a failed ISO build (because the livecd.sqfs file is too large for ISO).
When you run the utility choose which you wish to use .... an ISO or files such as are available in a live session ..... those in your workinging directory under /livecd.
If I can't remaster my install and /home (because it is too big) then I might as well start with the iso file from the PCLOS site and tweak it after I install it.
There is a limitation on the size of any file that the ISO can contain ...... which is 4GB.
The original PCLOS ISO contains a file that is less than 700MB.
So there is quite a lot of space left for additions before you hit the 4GB limit of the ISO ...... remembering that this is a compressed file size and equates to about 11GB of installed size.
That is not to say that your full install cannot be remastered ....... as it can ...... you have done so, and the files are in the working directory.
What cannot be done (presently) is an ISO cannot be created of those files of the remaster, because it would break the 4GB limit of the ISO.
The alternate is to use LiveUSB Creator, which does not require an ISO, although it can use one.
Doing this allows a remaster on removable media without the need to first create an ISO, which is a requirement of creating the remaster on optical media.
I have during tests remastered installed systems that were greater than 30GB, and successfully booted them from a LiveUSB flash stick, after running LiveUSB Creator.
If you have a suitably sized flash stick then I suggest you try it ...... particularly if you need to keep a lot of data in your home partition.
On the other hand I think you might find that there is a lot of stuff in your /home that is no required which would reduce the size needed quite a bit.