How many know their actual pin weight. Serious 5vr's should. Most discussion regarding trucks are more about towing capacity, when it needs to be about pin weight which is the biggest part of cargo ...
I agree, most don't know their actual numbers, I don't. If I had a scale reasonably close, I'd give it a run. I am well under my payload, rig tows well, so not a big concern.
If I were to guess at my pin, or loaded weight, I would go by my dry weight, plus 1,500#s, for my loaded wt, and then figure 20 percent of that for pin wt.
If I was even close to maxing out rawr, I would take the time, when traveling, to find exact wts.