On the screw holes, the procedure is to drill the hole, mount the servo, remove the servo and add a drop of thin CA to each hole, let dry. What that does is harden the area and the "threads" in the wood made by the screws inital passage. Once dry mount the servo. On the "servo hole", I mean, the rectangular cut out in the fuse or wing that the servo sits in. If its too tight, as in having to force the servo in due to the tolerances being too tight, just sand the opening a little so the servo goes in to position easily. If the hole is too snug you again cancel out the isolation factor that the rubber mounts provide. I guarantee if you back off on the servo mounting screws slightly allowing the servo to rest on the rubber the twitch will go away. Joe