My pref would be as much positive caster as can be mustered.1/16-1/8 toe in/zero camber. first set the ride height to where he likes the look of the front wheels in the wheelwells. are you aligning it yourself with gauges or doing it on a regular rack? if yourself: half tank of gas/tires aired up/his weight in barbells on the dr seat. if at a shop, some alignment machines automatically compensate for drivers weight, no help there, if a shop is doing it with your supplied specs ask them about that. for a premium job I would set the cams for max caster then turn the rear one(s) till you get zero camber & straight ahead toe in & FIRST set the ride height then drive in some miles to let everything settle then recheck but this might be too much unless he was my brother in law (you know what I mean). I forget if toe or camber is adjusted first.