So a few months back when I was researching what suspension lift to get I couldn't find much on hauling with Wheelers progressive HD 3 leaf AAL so now that I have it I thought I would share.
I installed Billies 5100 all around, front set to 1.75 and have the Wheelers HD 3 leaf pack on non-tsb springs with the overload removed. Initially the truck sat with a bit of a rake but now that I have hauled a loads with it it has settled, still has a slight rake though. I was hauling half yards of crushed rock which according to the internet is about 1300# of material. The truck did quite well with the new leafs added. I was not riding on the bump stops and it handled decent for so much weight, given I didn't drive very far and wasn't going that fast.