I just thought of that myself. I cut a slot with a cutoff wheel and got the last screw out with a slotted screwdriver.
I wish I would've thought of that several screws ago, :BangHead: before I bent the channel. :(
It seems that I figure out a problem, or get good at a given technique just as I finish a project. Could be something around the house, or on a car. Like in this case, I'll probably never remove a windshield and the stubborn clip screws again. It's a one time project.
Oh well. I figured I'd post my solution for anyone who may search this in the future.