Up front, you want to make the driveshaft angle correct, but the caster is much more important for day-to-day drivability. The more lift you throw at the Jeep, the more you change the caster. Positive caster is when the upper ball joint is behind the lower and negative caster is when the lower is behind the upper. You want to adjust it for about 5 degrees of positive caster, which helps the steering wheel return to center and minimize wandering. If you've already got death wobble, however, sometimes less caster is better.