I have almost the same set up.
I have a Zone 4.5, w pro comp shocks ( ordered Bilstein but where back ordered forever) and I have Firestone airbags in the rear. wheels are Black Rhino Sierra 18x9 12 offset and General Grappers 35x12.5x18. They did get a spacer for the airbags, but I did get to keep them. I hate sagging when I tow. I keep about 20psi at all time to help smooth out the ride, and it does give a very little rake.
Hope that helps.