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I'd say from your third picture it doesn't look like you have any angle on that rear u-joint. U-joints need to have a little angle on them to keep the needle bearings spinning; at least 1° If not, the U-joint life will be severely reduced. From you numbers I would say you want an 8° shim to angle your rear-end down to like 1.9°. Typically with leaf-springs you will go a little past equal angle between the transfer-case and the rear-end. If your powertrain is angled at 2.2° then you would want your rear-end angled at almost 0°. This is because when you put torque to the rear-end the pinion wants to climb the ring-gear and the leaf springs will flex in an S-shape, called spring wrap, letting the yoke rotate up.The problem with U-joints and lifts is that a U-joint has a practical limit for a working angle. Typically this is going to be around 15°. They can go steeper angles, but even by 15° the U-joint life is drastically reduced. For you your working angle at the transfer-case is 11° and your working angle at the Rear-end is 3.3°, assuming your measurements are accurate. If you put in an 8° shim then your working angle at the rear-end will be about 11.9° and your working angle at the transfer-case will be about 11.6°. Your driveshaft will lengthen slightly, so you want to be sure that you have proper engagement of the slip-yoke. Depending on your engagement now at the slip-yoke, it might have to be lengthened. I think you want to be sure you have at least 2 inches of engagement. That could be another source of vibration.
My measurements below were pulled using the Tremec driveline angle finder.Transfer case: 2.2 degreesDriveshaft: 13.2 degreesRear pinion: 9.9 degrees