Mike, You sound like me...i've got planes ranging from quarter scale areobatic down to 20 size planes of all shapes and sizes but like you I still like to keep and fly the trainer types and let friends and family try their hand at it. The Avistar even with the 11x5 APC will boogy and get right out of the water but there are several props that are good for the float plane as well...APC 10.5x6 is also a great prop for the float plane and I think I tried a 10x7 with success. One of my favorite trainer type planes is the Sig LT 40. I set mine up with out so much dihederal and put a TT 46 on it. It rolls good, does a good knife edge flys inverted very well and will absolutely hang on the prop for as long as I want to hold it. I've not tried a set of floats on it but i'm sure it would do great.