I match drilled the tip to the wing. I drilled holes for the nutplates. I countersunk all the holes for flush rivets I riveted the nutplates on.
Instructions say you don't need backing aluminum strips if you are using nutplates. But I've got a Piper Cherokee that has some nutplates riveted to just fiberglass parts and they do come lose after 25 years. So I'm using the aluminum strips.
I did leave off the nutplates at a position where the VOR antenna will go. You'll see that next.