I had the problem where my sys 80's glass would not come out as it hit the wall.
So i modded the cab.I took out some of the screw nails holding in the rails.I then cut the plastic glass guide,so now when the glass comes to this cut point the glass comes out.And because sys 80 flipper buttons go from in to out the rails slide over these to hold them in place,and the lock bar holds the rail too.