Agree with all the others here, most these older 20-30 cars have flat glass. I make my templates from masonite, templates are a good idea, and necessary if your tops chopped, have a glass shop cut them same size as your template. Most shop's offer different tints, and you need to use laminated safety glass, I remember on a previous car , I used the same grey tint on the windshield as all the other windows, needless to say a guy with night blindness shouldn't have done this, oh well live and learn. If you do make templates for all your windows, if for some reason one gets broken, you will have a pattern to get one made, could save some valuable time.