Thanks for the help guys.

Ed: I use a 10x6 on my Tower .40, so I may take your advice and grab a 10x5 and have a go. Unfortunately I wrecked my plane, and am now building an Easy Sport 40 ARF, I'll put all the same equipment in though.

Still don't know what I'll buy for an engine, but I definitely have an idea of what to get now. Hopefully I can fly on floats over the long weekend, have to get used to the new plane first.