[Pyrotechnic]

I would recommend rather than swapping springs, just take some leafs out of the ones you have. Mine is a heavy half and it came with 8 leaf springs that had a ridiculous overload spring. I took out the overload plus another one on in the middle of the pack somewhere and it made a big difference. It rides much smoother and it lowered the rear pretty much level with the front. I can still haul a load in the back too no problem.

Keep in mind, a longer leaf spring will actually ride much smoother than a shorter one. If you take some leafs out of your long springs, you can actually end up with the same spring rate but a smoother ride than the short springs.