It sounds like you are more into drag racing then normal street driving. If that is the case pinion angle should br one to one and one half degree.
I have seen slapper bars adjusted with zero to two inches and they all worked ok on the car they were installed on. It depends on the car and tire combo.
try to remember that the adjustments are made for reaction times at the track. More clearence less reaction time---less clearence the quicker the reaction time.
If you drive mostley on the street you need some clearence to maintain a good ride and not bind the supension.
I hope this helps.