[dsraven]

I found one thing that works well for getting the cab and box in the same plane is a sting line set along the body line from front to rear. I know the rear fenders have some adjustability in their mounting but you could also use a digital level along the front fenders body line or simply the floor pan or running board step in the door opening then match the angle on the box rails. the string line does help for the box fenders alignment though