Like Mike said, a lot of ways to skin that cat. Screws are fast and easy, I don't like them, a choice thing. I have one plane with it held on with two colors of electrical tape to match the covering, it has worked out well and held on for a lot of years. I sometimes make a frame out of 1/8 balsa and glue the canopy onto that. I paint the lower inside of the canopy and you can't see the frame. Never use CA glue on a canopy you can see through, even if it's just tinted with Ritt Dye. CA fogs the plastic, you can buy canopy glue and it works very well. Just too many ways to mention. The plane I'm finishing up right now has a very long canopy and micro balloons and epoxy would look good with it feathered in. I may do that on this plane. Sometimes being able to remove the canopy is a plus.