if you are going to go that route, i'd suggest you stick with something that collapses and grips against the back side, not something that expands inside the hole. If you go with an 8' fiberglass antenna (i recommend the Digital brand by the way) and a good stainless mount, you should be able to use screws. the trick is to drill the hole the correct size so that the screws are neither too tight or too loose. are you going to use a solid mount or an adjustable mount?