I spoke to ARB and Tuftruck yesterday. For my application - stock bumper, but 5-600 lbs in the rear ARB recommended buying the light coils/shocks and heavy coils/shocks for the back (not the extra heavy, just the heavy) rather than the medium ARB 2" lift kit (RAM1500MK). Which is too bad, because I found a dealer in Canada with stock on the kit selling them at a good price.
Spoke to tuftruck, and you're right - there heavy spring is primarily for work trucks that will have a fuel tank etc in the back at all times. Suggested it would work well for me, but if I ever took the Decked kit and Truck Cap off it would ride very rough.
I'm seeing if I can source the ARB Old Man Emu parts separately here in Canada, or even just the light coil springs for the front. Suspect it will not be possible or will be a long backorder and not economical - we just don't sell the volume you do in the states. IMO, its going to come down to the OME Medium Lift kit or Bilsteins 6112 front/5100 rear with the Tuftruck rear shocks. I'm leaning towards going with the OME's, and replacing the front coil springs with the light coil springs from OME if needed. On road/off road performance is >> important than towing performance for me. Only tow occasionally, and if I really have a long/heavy trip to do I borrow a one ton from my father or brother's in law.
Plan to make my decision and purchase in the next week, will report back once installed and have some road experience either way.