When trying to square up my rear, the "pin" in the leaf springe is pretty much covered up by the laser cut spacer plate supplied with the springs. Even if it wasn't covered, there isn't a hole or recess in the bottom of the spring perch on the axle to line it up with. So.... Do you just line the "pin' in the spring up with the center of the axle? Where's the best place to measure from? The perch is beat up alittle so measuring from there i could be off as much as an 1/8". What's the minimum the rear can be out of alignment and still track straight? What am I missing? Help!