Caster & Camber VS Height

I would set it to stock ride height. Either one of three things is happening. Either the alignment shops you've taken it to haven't a clue how to adjust it, or you have some bad parts, such as control arm bushings, for example, or it has been wrecked at one point in time and not repaired correctly. I tend to think it is the first problem from your description. Most alignment shops nowadays look at older cars as a waste of time because they actually have to make caster/camber adjustments, instead of only setting the toe, so no one every really learns how to do it correctly. It's becoming a lost art of sorts.