Gonna try and help here. Bear with me as I will need to assemble some links to calculators and such.
The first one is: Fifth Wheel Weight Calculator
I will try to make some analogies concerning how all this fits together so please forgive me if I make it "too simple" or "too confusing." Analogies are never exact; they just try to get the principle across.
Think of your 5th wheel camper as a teeter totter with the main axles as the fulcrum. If there was exactly the same weight behind the wheels as in front; your "pin weight" would be zero. This would be a VERY unstable camper to tow and it would wag the dog like crazy.
5th Wheels need to be loaded "front heavy" from 15 to 25% of TOTAL weight "on the pin" to be safely towed. That means a 10,000 pound camper (actual weight) would need to be loaded such that between 1500 pounds and 2500 pounds of that 10,000 pound camper would be carried by the truck's hitch and the rest would be carried by the campers axles (8500 - 7500 pounds).
Now, lets say this notional camper has a maximum gross weight of 10,000 pounds. As shipped from the factory with all the cabinets and options, 2 30 pound bottles of propane and a 12 volt battery, it is "out the door" weighed at 8200 pounds "dry" weight. It will have a max cargo weight allowed of 10,000 - 8200 or 1800 pounds of cargo.
They will also weigh the pin at the factory and lets say the "dry weight pin weight" works out to be 1400 pounds.
so, your sticker will say:
Dry Weight 8200
pin weight 1400
max cargo 1800
They typically will put 2 - 4500 pound axles under this "notional" camper.
There would be 8000 pounds carried by the wheels and 2000 pounds carried by the trucks hitch if the camper was loaded correctly to its maximum weight of 10,000 pounds.
If you are loading your camper to its maximum capacity, LEVEL towing is very important because if the front of the camper's frame is lots higher than the back; since the front is supported by the hitch; less weight will be carried by the front tandem axle and more by the rear tandem axle. In this scenario, the rear axle could be overloaded by carrying more than its share of the 8000 pounds to be carried by the wheels. (like jacking up the front of the car; the front wheels slowly come off the ground and weight shifts to the back.)
Summing up, the DRY weight and Dry pin weights are good numbers if you tow as it came from the factory. no water, no food, no clothes, no generator, no toys, well you get the picture. So those numbers are useless EXCEPT for initial planning to see what different campers weigh and whether you are wasting your time looking at that AWESOME 38 foot long monster with granite table tops.
Use the maximum gross weight and 20% of the maximum GVW as the max pin weight for a more realistic idea of what you can tow. Remember your pickup has to be able to CARRY that 20% plus the weight of the hitch, cargo, and passengers.
But that is another thread.
Hope I did not lose (or confuse) anyone.