I put the dual aileron servos and operational flaps on my Nexstar. Just make sure you crank up the deflections on the ailerons after you do that. When you decrease the area of the aileron by cutting them for the flaps you'll need more deflection, or at least realize you'll need rudder to turn...

I got a kick out of a buddy I let fly it. He's pretty good with RC models and tends to forget about rudder unless he's doing a maneuver that requires it. His exclamation after the first takeoff without the higher deflection rates was "IT WON'T TURN!" I had to chuckle...