The aileron servo can be mounted in a couple ways.

Use 3/8" dowel rods and mount the servo on top of the wing. This method was considered.

This method was used: A hole was cut to allow the placement of the servo. The servo goes through the wing and is covered by the belly pan. The servo was mounted as far to the rear as possible.

By locating the servo farther to the rear a CG tank can be located near the center of gravity.