RE: Cobbling together a trainer
Scott, make sure you box in a seat for the new wing so it doesn't shift around. Than and making sure the CG is OK and it should work.
You might try using a smaller tank, this should give you three or more OZ weight reduction. Then again, it may fly just fine with the slightly heaver weight. OH yes. make sure the incidences are good with the new wing. Those fence post seem to always jump out, we've lost three planes at our field this year to them. Almost four, I don't have a clue how mine missed and went under the barbed wire.
When I was a kid, I used blind slats and aluminum tubing from a blown down TV antenna and made control line planes. I'ts kind of supprising what will get off the ground when prompted.
Don