Using a Dremel tool with a small diamond cutting wheel I removed the flange from around the canopy. I just cut the flange back to the bend. I can see a potential problem with the trimming. That is, the plexiglass dust that is produced sticks to the plastic protective sheet and keeps it from sticking to the glass. I need to find a way to keep the plastic attached to the canopy so it doesn't get scratched. On the positive side, I think the Dremel with the diamond wheel will work pretty well for the trimming of the canopy. You just have to go slow and cust a little with each pass.
