Personally what I'd do on something like that is use 4 geared Speed 400s, geared about 3:1, swinging probably about a 9" prop.

For wiring, I'd wire them in two banks, on two ESC's. The left motors, and the right motors, this way with a computer radio you can mix the two together on two different channels, and slave it to the rudder for differential power. 8 cells per bank of motors would be enough. Run CP1300s or the 1950 nimh cells for long duration.

--Paul