One other thing you can check and tweak is the tightening sequence of the 4 bolts that "sandwich" the spring to the rear differential cover: If the bolts are not snugged down very evenly and incrementally, the spring can actually get installed a little cocked with one side lower than the other. You can easily check this by pulling out the end bolts on the spring and letting the spring ends hang unrestrained: left and right sides should be exactly the same. If one side is hanging a little lower, you need to loosen up the 2 bolts on the opposite side and tighten the 2 bolts on the low side in order to cock the spring into a level position.
Another issue I've seen on a few occasions that will cause the uneven rear ride height is that the front springs are not installed correctly, or are not even. Make sure the front springs are not sagging, and make sure they are corectly rotated and seated in the seat pockets. Uneven front springs will cause a significant change in side-to-side rear ride height.
Lars
