You want to worry about your castor more than pinion angle unless your going to cut and rotate the knuckles. If its trailered and you don't go very fast offroad then maybe you can get away with bad castor angles. I'm still unsure of what the ideal castor angle is but I think stock factory solid axle castor was +2 deg but Ive read with large tires up to 6 or 7 deg is good.
