I believe that adding overload leaves to make your overloads contact sooner would be the best solution. On my F350 Dually I am just running the factory overload and air bags with about 45psi in them. The setup works okay, but the front end is slightly high when loaded because the way I described above makes it so that the front bumper of the overload is just contacting and the rear not at all. There is a chance that this is wearing my tires faster when I'm towing with the camper on the truck. Torklift makes a product if you don't want to add a leaf. It makes the overloads engage sooner. You could make air bags alone work fine. Especially if you have overloads and a rear sway bar.
I just finally found a rubber bed mat for my 350. I've run the camper in it for a year and a half and it was always moving around. Especially that one time a deer decided to cross in front of me at the last second. The brake application caused a bit of a shift that left the front turn buckles a little loose.
You can mix the types of turn buckles if youd like. As long as they are long enough. I believe that mine are spring loaded in the front, but not sure about the rear.