Z bar alignment

I don't think a shim is going to help you. There isn't ton of extra room in the Z bar assembly anyway, not enough to fit a substantial shim. If the ball stud is crooked then either the ball stud failed or the mount did. The ball stud just has a short threaded stud on it, there's no reason for it to be crooked unless something broke. The other possibility is that the end of the Z-bar split, which has also been known to happen.

Before you plan the repair you're going to have to pull the Z bar out and find out what's broken or damaged. Probably a good time to install new bushings too.