A Saito 100 is not too much power if you know what the throttle stick is to be used for, nor is it too much additional weight. 16 x 4W prop clears the ground just fine.

Inverted enignes seem to be a flooding problem when they are new and just being broken in. After run for a while you can lean the low end a little, then just make sure the carb is closed before you fuel the plane.

Ed M.