I would say .060"lexan should be plenty thick. I think that is what came in the earlier kits. Actually I used .060" lexan for the windshields in all 4 of my Avid Flyers, but at about 100 MPH, the windscreen starts to buckle back against the tubes. Seldom if ever hit 100 MPH with most of them, so it wasn't a problem. On the Kitfox 4 I'm rebuilding, they used .090" lexan for the windshield. JImChuk