But without a slip yoke eliminator and cv driveshaft in the rear, adjustable rear uppers will cause you problems. You do not need to reset the pinion angle in the rear without this. If you do not understand, look at your front driveshaft, it is a cv type shaft. You may not need adjustable upper control arms at all with a 3.5 in lift. with a cv type shaft, the pinion needs to be in line with the shaft to eliminate vibrations, but without it your u joints need to run at the same angle, like your rear shaft is now.
If there's a will, usually there's a way, but then you get to that bolt that you still can't get to with two extensions, two universal sockets, and a contorsionist midget trying to help you.
1999 XJ Four door, mostly stock for now, but I am in the process of building a custom plate bumper.