Hi (again) Gene!
I would suggest any model that is around 650-670 sq. in. and under 70 oz. My USA-1 might have been my best airplane ever and it was powered by a T&L ST G.51. Of course it was 700 sq, in and 54 oz RTF.
Most any of Randy's models, the Legacy, a Saturn, Gieske's Bear, Al Rabe's Classic era Bearcat and Mustang, etc., should work with this engine.
Pat Johnston has a couple of planes that are perfect for this engine.
Bill