I noticed that Rough Country *may* have a helper spring system for the Lightning. I have not contacted them on this, but it might be worth looking into: https://www.roughcountry.com/air-spring-kits/ford/f-150-lightning/2023Bringing this back up, I think this idea would be great- soften the rear springs for normal usage, and add air helper springs that can be inflated when the truck is heavily loaded.
Looking under the truck, there are elastomer bump stomps that are separate from the coilovers in the rear. Does anybody know of an air helper spring that goes in place of a bottom out bumper that serves both functions?
Combine that with softer coil springs.