ORIGINAL: DavidAgar
Your # 2 is the way to go. Mount the servo's in between a couple of the ribs at about the mid point of the aileron and use control horns and a short pushrod. You can mount the servos anyway that you want to. I prefer to mount them flat so all that is sticking out of the wing is the control horn and pushrod. Good Luck, Dave
I'd have to agree with David here.
Easiest way is to glue two 1/4" square stock sticks between two ribs about 1/3rd of the way out in the wing panel. Keep the distance between the sticks at least three inches and about 3/32 of an inch below the rib and as close to the wing spar as possible. This is done so that when you glue a servo mounting plate on it will be even with the rib surface. Then find ya some 3/32" light ply and cut yourself a plate that will rest on the sticks and make contact with both the ribs. Cut a hole out in that plate to fit your servo. Save the piece removed to serve as a doubler to where your servo screws will go in to hold the servo. Now glue your servo plate in and make sure it has good contact with both ribs. You should have a pretty solid mount.