Pinion Angle

That is also my understanding. You need both U-Joints to be in Opposite Flex in order to cancel the "Chug" of an Elliptical Rotation...

In lamen's terms I guess, you want the pinion gear and the output shaft to be Parallel or "the same plane". The driveshaft angle is a wash in this application. On High trucks you need to worry about that because they can bind up U-Joints at severe angles with a lot of Torque and Load.