What do I need to tow 5th wheel with RAM 2500 Megacab?

Major Dad wrote:

fla-gypsy wrote:
That 1265 dry pin weight will be more on a loaded trailer. Payload may be a real concern

That is another question...is that pin weight dry weight, or is it based on gross weight? The trailer's cargo capacity is about 2055 lbs, so do I take 20% of that and add it to the pin weight? If so that would be a pin weight of 1677 lbs, which SEEMS to be well under my 2140 payload.