Alignment advice needed?

If the caster is not the same from side to side it will cause a pull. Postive caster improves straight line tracking so if one side has positive and one side has negative it will pull to one side because the one side wants to track straight while the other wants to not track as straight. This works real well on a circle track car because the car wants to turn into the corner you just have to fight the car a little in the straight.