When in doubt take Steve's advise over mine.
The car should pull the to side with lower caster. I will edit my previous post to correct the error. Caster is frequently used to help a car go straight with less steering effort in the right lane where it wants to drift to the right. For the purposes of correcting road crown 0.25-0.5 degree is commonly used. Florida roads have a lot of crown so 0.5 is commonly used. In states's like GA or TN where there is less crown, 0.25 may work fine. I believe Steve is saying 0.3 is negligable for correcting your problem.