I need to get my rig into a "roller" asap. \It's up on jack stands. I have the axles all ready to go as well as the leaf springs, hangers, brackets, etc... Roughly what should I be aiming for on the shackle angle with the vehicle on stands and no weight (i.e. axles hanging from) on the springs? 54" front springs, 60" rear. Both springs having the shackles at the rear and fixed eye up front.