RE: .76 engine in a trainer??
Do not put an engine that big in a 40 size plane. You will tear it to shreds. It will be slightly large even on a 60 size trainer. I would get a 60 size and glas the center cection of the wing. Then I would fly it with a little caution on the trhrottle. You should be ok with a 60 trainer. Good luck.
Mark Shuman