as one who likes to try diff things was thinking about adding flaps to a 70in 35cc extra.........what do you think?

Just for grins why don't you try flaperons and see what you think. I did it just for something else to do, also tried spoilerons. Went back to aileron Diff.

Are you trying to fix an issue with flaps or just wanting to try them? Full span flaps like on an Extra can cause tip stalls.