RE: trainer to 1/4 scale
A 1/4-scale Cessna will be easier to fly than a .40-size, but I agree with Bubba. The Cessna will seem quite fast compared to the Avistar, especially on take-off and landing, and getting too slow on final could easily be disastrous. You could fly it, but you'd be back in learning mode for awhile, with an expensive plane at stake.