After much internal debate and a conversation with Nick, I decided to mount the servo to the top skin of the aileron instead of to the access cover plate. The advantage of the access cover plate is that no screws or washers would be installed on the top of the aileron. Both visually and aerodynamically, this would be cleaner than mounting it ot the top. The downside is that it's a pain in the neck to add spacers to get the angle of the rod correct to clear the lower skin.
I choose fast, simple and easy over complicated and time consuming.
So the process was to set nut plates on the servo, set to neutral, set in place, match drill the aileron, countersink those holes, use timmerman washers and round headed screws to mount the servo, and test using the bench battery borrowed from my golf cart.
