Max pin weight for 2500

Is it YOUR truck? If so, take the truck, with the hitch in the bed fully fueled to a scale. The really important weight is the real axle weight. The difference between scaled rear axle weight, and the sticker in the drivers door / door jam is the max possible weight. Real world there will be more then just you in the truck, and possible something (like firewood, coolers, bikes, etc) in the bed. So shoot for several hundred lbs below the max possible. Back seat passengers and cargo put roughly 1/2 their weight on each axle.
I prefer to keep within all ratings, but legal is axle & tire weights.