I have Super Springs with a 5500lb wet load, and they are simply FANTASTIC! I have Helliwig Big Wig, made very little difference.
But the the add on to the Super Springs that totally controls sway is the FRONT Timbrens.
The Combo of Super Springs(raises camper to original bed height with brute controlled strength)REAR & Timbrens FRONT(stop bounce & porposing.), Just Amazing.
My Super Springs are for loads 6000lb plus Commercial, made especially for Amoured Truck & Extra Heavy Loads. These are the heaviest they make.
I have a set of Stable Loads in a box, yet to be installed. This may be a project soon,
to add yet just a little more sway control.
However, the weakest point of my or anyone else's Truck is the tires!
Dual Rear Wheel Rickson's may also be a solution, for added security, knowing that with commercial 19.5 inch tires, much needed strength and tire longetivity is achieved.
We all safely tweak our ride to get the best performance & capability we need,
whilst understanding safe load capacity and insurance company & regulatory
demands.
This is what we do for very Heavy Loads, a learning exercise!
Enjoy Your TC'n.