The way you know you got it right is if you sit in the driver seat and can’t see a darn thing out of the back! We ran one in high school and all I remember is I could not see any thing when changing lanes or backing it up! Great cars and I love the louvers on the back glass!
My asshole brother had a 71 Mach 1 429 SCJ drag pack car in the mid 70's. I remember some crazy fun rides in that car, and yeah, with the angle of the rear window, there was little visibility.