Sorry I can't help you with your direct question. However, for reference, i have a 3500 drw Silverado and I find that if I air down the tires 10lbs each it smoothes out the ride some without losing any ability to tow what I'm towing. And I'm probably not telling you anything you don't know but thought I'd share just in case.
Texas Outdoors - Landscape Contractor
Licensed Irrigator - LI19906