Jon,

Just another thought on making things a little easier for your addition of flaps... You may think about using the single servo location and the existing aileron control for the flaps.

I think the Telemaster uses torque rods and you just have to make a "Y" connector from the servo to both rods. They use this setup on planes like the Carl Goldberg Chipmunk and it is easy and works well.

Then you are just adding two servos into the wing and less cutting/fitting.

Edited to correct: Oops, I just checked that the Telemaster has separate aileron servos (the Nextar uses one servo in the center), so my suggestion won't help... Unless you split the trailing edge off and add a torque tube setup with just 1 servo...