@DRANGED if you gonna put 1000# in the rear and then DD on the light side, that’s a tough load to manage!
You need to move up the heavy progressive springs and might need the supplemental air bags to insert in the rear coils to hold them up.
From the 4R web site:
C59-675V - Variable rate comfort option, stock rear weight, 2.5" lift. 470/470mm, 16mm wire, 157-230LB variable
C59-677V - Variable rate comfort option, 400+LB heavy rear load weight, 2.5-3" lift. 500/500mm, 16mm wire, 157-230LB variable
C59-701V - Variable rate, 600-700 LB heavy rear load weight, 3" lift, long travel. 500/500mm, 17mm wire, 210-245LB variable. Designed for those with heavy full rear bumper, tire carrier, roof rack, RTT, drawers, and fridge. Rides very well with all that weight, as well as when loaded even further.
C59-749V - Variable Rate,
750-900 LB super heavyconstant rear load, 3" lift, long travel. 520/520mm free height, 18mm wire, 198-300LB variable rate, usually around 270LB at loaded height