Success! (touch wood!)
Ok so i followed some of the advice given in this thread, and found a few other options that made it work for me, as far as I can tell. I had to use the 2xUSB keydrive method as Grok explains here, with a little modification:
https://grok.com/chat/2e8fc626-eace-453 ... c9809b6e23
So i ended up using Rufus for the initial Live USB1 install and then used MX Live USB creator to "clone running live session" onto the second USB2 key drive. Then after removing the first USB1 drive that Rufus created, i booted into the second USB2 (F12 on my laptop brings up the boot menu on boot up) and set persistence options in the advanced menu selection. I went with persist_static, this then gave the options to set the default sizes for "rootfs" and "homefs" during that intital boot into the MX Linux environment. After that first bootup into this USB2 keydrive I installed some things, made changes etc to test persistence was working.
Note: after shutting down and restarting, IF i just boot right into the MX Linux "desktop" it looks like a normal Live session with no persistence. I have to first select the persistence options in the advanced menu, picking that persist_static option to get my changes to load back in. So a small hoop to jump through, it does not automatically boot up with persistence, but it is a small menu manipulation so i'm not worried about it.
The one thing i'm not sure on is keyboard and timezone settings? I did also set those up during the initial setup (my keyboard is French and my timezone is Brussels in Belgium! But my language is English) but it seems these are not kept in the persistence files? I could be wrong on that, and maybe just got nervous seeing them back to defaults before booting into the MX Linux "desktop" environment, so changed them again, just in case i got a keyboard that did not work as intended!
Anyway thanks to all the pointers here, i'm seemingly now working with persistence, which is a huge relief, and i'll test this all out over the coming months and report back on anything i think might help others trying this out. I'm looking forward to my MX Linux road ahead and coming from Linux Mint feel pretty at home so far. Thanks to the devs and guys and gals that made this really nice looking Linux
