I Think if some of you look closely you'll see that the white Nylon(not Plastic) guides are worn causing the glass to tilt forward. Since everything was originally designed to go straight up and down, when the glass tilts forward it binds up. All this "cut off weather striping and rubber gasket" is unnecessary!. If you take off the inner door panel and watch those white Nylon tabs you will see what I mean. Operate the window from "down to up" position and you will see the glass pressing against the inner front of the nylon brackets and there is a space behind the glass and the inner "back" side of the bracket. If you then pull the window to stand up perfectly vertical the glass will now come in contact with the inner back of the bracket and there is a space in the inner front of the bracket,,caused by wear and tear. So obviously if the space was not there the window would be held in a perfectly strainght vertical position and the window slides perfectly with no binding.
I believe I have a very simple fix that is almost Free!. Get a nylon zip tie that is the width (Thickness of the glass) and insert it into the space on the inner front of the bracket to take up the "play". I figured this out conceptually a while ago but ill health and lousey weather prevented me from actually making the fix.
Maybe some one in the group with a garage or warmer weather could try this fix out and tell me if it works. It should!
God luck guys!