Kirknik,

I am using a single standard servo to operate my flaps. My flaps run from the fuselage to the nacelle. They DO slow the plane down and they DO cause the model to pitch up when deployed (therfore I have set up my Tx to mix in some down elevator to compensate). If I were to do it again, I would do as William suggested and extend them 1 rib bay beyond the nacelle (I'd probably connect the outboard section to the inboard section with a short but beefy torque rod. I would also increase the flap chord by about 1/4" to 3/8".