Nice work on this build. To implment the dual servo set-up in the ailerons, you could mount both servos in the center of the wing and use each to drive 1 aileron. I did this for a Senior Telemaster and it worked out fine. The other way I have seen this done is to mount the servos in the wing panels (as you are doing) and drill half inch holes in each rib between where the servo is mounted and the center wing to run the servo wires (and extensions) back to the receiver. If you need some ideas as to how to mount the servos in the wing, take a look at the instructions for the Sig Four Star 120. The instructions will show you two methods to create the servo mounts.