I'll second this method. I've used it on all my planes since I built my first 4*60. The ribs need to be about 3 inches apart for this to work well. You can also get it into some very thin airfoils. The main reason is that the movement of the servo arm is on the same plain as the movement of the aileron horn. That and it a very clean looking setup and very easy to cover around.

Don

Added, there is no need to re-enforce the ribs, just use a hard wool mount for the lid. Glue one along each side rib, and one across the Spar and then a cross member between the servo and the TE. I've crashed four planes with this setup and if the servo came loose, it was because the rest of the wing was destroyed around it. It is a very tough mounting.

Don