I'm running a Magnum 61 four stroke in mine and it is plenty of power for the Pup...even off the water on it's floats. Any more and it would be wasted. Frankly if you are facing a constant 16 to 20 mph wind you are building the wrong plane. This plane is a floater. It will land slower than you can walk. In that kind of wind it won't last long. build something that is faster and has a better sink rate.

Good luck

Bassman