1971 door glass removal help.

Have a 1971 Duster I’m trying to gut the doors and I can’t get the philips head screws on the bottom of the glass to come lose. I turn the heads and the round thing on the back side spins also. I’ve tried to use vice grips on the back side to hold it but no luck. Any tips or help on how to get them out ? I can’t see how to remove the glass without getting these off the glass.