Have you tried re-ironing your pieces to see if the paper will come off easier when it's a bit warm? I've done my fusing & left the paper on for weeks before fusing onto my base & not had any problems.
I usually peel the paper back on a corner before I draw on it, just to make sure I'm writing on the paper that has the sticky on it - voice of experience after having to redraw a bunch of times! :lol: