I bought stock replacement springs for a 60 years ago from M_A_F_ and they sagged immediately. This was a daily driver, and they wanted me to send them in for evaluation, which I couldn't do. I took the truck to a local spring shop (Black's in Zanesville Oh) and they laughed at the steel the springs were made from. They re-arched them for me and added a leaf for about 1.5" of lift. After that they rode awesome. Black's said they could have built new springs for less than I paid and do all the labor (stuck, frozen parts, etc.). I have since installed two OME Dakkar kits and totally pleased with the quality. My 40 needs weight to be considered smooth (still no Cadillac ride). I am considering removing a leaf (leaves) when the hardtop comes off, should make for a smoother ride -and better articulation-. You may be able to remove leaves to soften, but may lower your ride height as well. Where is your truck from, where has it been- shackles may be rusted & not moving. Don't be afraid to flex.
If I wanted a stock ride I would have new springs built locally. OME Dakkar is reasonablly priced and I'm pleased with the quality. If I was rich or just wanted to go bigger I would totally go with Alcan.