I solved my problem by calling my friendly auto repair guy, five minutes from the house. He said bring it in, and he had it done in a few minutes minutes. No charge. He used an air driver on the locking nut and wedged a screw driver in the window channel behind the screw head. I cringed thinking he'd break the plastic sliding jaw but it didn't break and the screw is secure.

I looked at the clevis pins but thought they were too long, even cut off, but I didn't know how much clearence there is in the door panel as the window is run up.

The "bolt" I used is probably more accurately called a flat head screw with a slot.

I would really be interested in hearing from those who have used a bolt/screw and nut solution and how they actually assembled it and the jaw into the window channel. I suppose this will happen in my other windows sooner or later and I'd like to know to do it. I'll probably go the clevis pin or maybe drill the rivet and use a cotter pin.

Thanks for your responses.