You can order a glass cowl from Fiberglass Specialties, I think there cowl will fit the GP, CG and SIG Cub without a problem, it needs to be cut to size. I made up new windows for a CG Cub by cutting out a tracing of the windows then cutting forms from 1/8 light ply, used K&S plastic and my heat gun to make new ones. I heated up the plastic, set it over the wood frame and pressed the cut out over the hot plastic to form them. Worked for me.