alignment question?

[texastrendz]

I have a 1 ton dually that has custom upper and lower control arms and that has been back halfed with a triangulated four link. I have not found an alignment shop that will touch it. I have got the toe and camber pretty good on the truck but it pulls pretty hard to the right. I have read that the caster can cause pull in the vehicle. I have the rearend nice and square in it as far as a tape measure can measure. Do i need to buy a caster guage to set this up or is there any way around this to set the caster? How many degrees is a streetable setup have in it? Any and all help would be appreciated, thanks Daniel. It is a 88-2000 body style.