As far as Google goes - Google "pinion angle" and you will be led to a variety of opinions, forums, and "tech" articles that pretty much mirror the posts here. Many simply call "pinion angle" the angle of the rear u-joint - many others call it the angle between the centerlines of the engine/trans and the pinion. I could post on a forum that you need a pig in the trunk to set correct pinion angle and it would appear on Google and somebody would believe it and quote it on a forum. So you can quote 10 that agree with you and I can 10 that agree with me and it's still just matters of opinion.

So here's the rub - call it what you want - pinion angle, rear u-joint operating angle, WHATEVER - only setting the rear angle to a spec and not referencing it to the trans is inviting driveline vibrations and reliability issues. Automatically turning the pinion nose down when the trans is also tipped down results in operating angles that are not parallel and results in a weaker driveline and possible vibration issues. I call pinion angle the total package - referencing the pinion to the engine/trans centerline - obviously you do not. To reference to pinion to the trans, the driveshaft does not need to be in.

So looking at the BIG PICTURE, when you consider strength and vibration, if your driveline angles, pinion angles, whatever you want to call them, are like the lower picture UNDER POWER and not parallel THEY ARE WRONG. The pinion doesn't get driven at a constant speed which is crucial to maximum strength and minimal vibration.