I'm sure your cars all look fantastic, but when I chopped my '53 Chevy and laid down the rear window at the same angle as the beltline trim the '50 Ford back gl*** I have was too round and humped in the middle. I worked against the lines of the car instead of with them. And the only one I ever saw in person looked wrong for the same reason. Just sayin... I'm sure the angle of the laydown makes a big difference. For my chop a '48 Chevy window was near perfect.
1949 dodge rear gl*** can work,it's less than an inch different than the 49 Chevy gl*** used in these chops. There is one for sale on hamb marketplace
I used a 46 ford sedan rear window http://i1273.photobucket.c om/albums/y406/raysnewbucket/IMG_20140922_035237_zpslbfq9xuf.jpg