Pinion angle - have a vibration
It is so easy to add wedge shims under the spring perches to test an angle adjustment. Just buy a few shims of different angles (Jegs or Summit has them) and pop them in from smallest to next one larger. Take a test ride after each and see if the problem is better or worse.
BTW, the angles are trans rear = up and diff. nose. = down. If they are both up or both down, then you will have a very bad vibration. (was that a Beach Boys song?:protest:)