That all sounds fantastic Zetro - I guess if you can avoid REXX running it would be better and you could place your updaters in the Programs DIR, but it all depends on what you decide is best as I'm no expert in REXX or C.
One things for certain - you are doing everyone a great service putting together this guide. Make sure you credit yourself and perhaps give EAB a little plug in their somewhere!
Certainly, if you manage that layout in one drawer it will be easier for you to release update packs that simply drop into place over the old one.
Thanks for all your hard slog in getting this moving forward so swifty, and taking ideas onboard.