without getting into any of your numbers/measurements---------pinion /driveline angles are angles of the pinion,driveshaft and transmission out put shaft to each other-NOT to the ground--------altho some of these can be measured and worked out , the angles to the mothr earth are irrelevant--------its the u-joint angles and also don't forget that that also includes sideways if you have engine or rear end offset from centerline------


AND---the thinking about the pinion angle changing on acceleration does happen, however, remember that the rear wheels/axle are on the ground and it is the movement of the chassis up/down that is the prominent motion that changes the angles-----