Tom, use a hole duplicator to locate these holes, it worked great on my -9. No chance of miss-drilling the hole this way....On the same subject remember that to drill the sheet metal piece that sticks out from the fuselage on each side you need to have the holes marked with "lead lines" that indicate the hole should be 3 inches down the line and draw these before mounting the wings for the first time so you can match up the holes even though you cant see the ones on the wing root when they are installed...