My idea exactly, build a twin in the 40 to 60 range and power it with two 30 or smaller FS engines. The twins I have seen, and that ain't many, were vastly over powered. (I like scale flight, I'm not a hot dogger)

I have a friend that has a 20 lb CL-415 adequately powered by two Irvine 53's. It got off the water nicely it's first flight.

Smaller engines is the way to go for twins.