Driveline angles

The driveshaft angle is a red herring. The two angles you need to know are the transmission output shaft angle and the differential pinion angle.
I've never observed that. I've set up many vehicles through the years. Set them up correctly according to various driveline diagrams. If it was a Mopar, I went right by the Mopar suspension manual. Same with my current 64 Valiant. The end all be all is, if you follow correct instructions, you will not have an issue.