Great job. Wish I could have been there to see it. For giggles, if you pull again, you might try putting matching marks from wheels to tires in the back to see if the tires are spinning on the rims. As I understand it, as long as the tires don't break loose you can let more air out. Of course that was what we were taught for military 2.5 tons.

195? Chevy 3800 dump truck
1973 Chevy C30 cab and chassis
1987 Suburban 3/4 ton 6.2L Diesel