Keep it light as you can! I'm using an OS.61FX and will need about 6-8ozs of wieght in the nose to balance with no landing gear. I'm thinking a four stroke or a large 2 stroke might need a lot more.
Also, my kit had aileron hinge slots cut for two hinges apiece...I made it three apiece, same as the flaps. Strange, I would have thought it would've been the other way around.

Allen