Where ever you get them, DO NOT buy them from JC Whitney, I bought rear 7 leaf HD springs and they had about the same arch as the worn worn sagging stockers I took out, all in all, I only got about a half an inch lift, and was still sagging. I think the best bet would be to buy a 2" soft ride lift kit from Skyjacker or whoever makes them, get 2"lift and a softer ride. This is only what I've heard from the TDR members that have gone through this same thing.
How long has it been since they were rearched? Do you haul heavy loads? If it hasnt been very long since you had them rearched, you can try taking the truck back to the shop that did the rearch and tell them your not satisfied etc, and have them rearch them again, this is what I did with my front leafs. Less than 12 months or 12k mi warranty from this local shop, rearched them to my specs for nothing.