RE: Benefit of two aeileron servos - could i make this mod to DPS?
The way I actually install dual Aileron servos is to find the approximate center of the aileron (not the wing) and mark a spot at the same place on each side of the wing just behind the spar. I then take a servo and position it so that the hole in the servo arm is over top of the mark but remember to use opposite sides of each servo so you won't need to reverse one servo. Also keeping the servo to the inbound side will make your servo extensions a little shorter. I position it so that the servo is just behind the Spar so that the screws on one end of the servo will thread into the Spar (make sure the servo lead faces away from the spar). Trace around the servo and then cut a hole where you traced. One end of the servo will screw into the spar (predrill) and I usually cut a small piece of PVC and glue it inside the servo opening to give the screws on the other end something to bite into. The linkage should be installed just like any other control surface but I do use a PVC backer the whole width of the aileron under the control horn.
I hope that helps some.
If you have a local flying field this will make a lot more sense if you look at how some other planes with dual Aileron servos are setup.