-->Here<-- is the thread where I put the specs that I use to set up lifted X's. Depending on the amount of road crown that you have in your area (we have a lot) will determine how much of a difference in the caster angle that you'll need to overcome the draw to the right.

0.5º is about max, 0.2º min (less than the right side!) is what you want for the caster. But definately, never go negative with the caster.