In this case my owners manual for my truck is rather specific (I think anyway).
It lists out how much they are giving for passenger weight and how much 'stuff' they put in the truck with them.
The corresponding weight limits assume occupants fill seats from the front of the vehicle to the back, each occupant weighs 150 lbs (70 kg), and each has 15 lbs (7 kg) of cargo in the cab, pickup bed, or In-Bed Trunk. Any additional weight, including cargo or accessories, reduces the maximum trailer weight and maximum tongue load.
I weigh 200, my wife weighs 135, and my 2 girls weigh 45 and 40. So --> 2.8 'Honda People'
At 3 Honda people I am allowed 4750lbs of tow weight and still 600 lbs on the tongue. Still well within the max trailer weight my X17Z would have in it by 1250 pounds.
That is the math that led me to the X17Z. I will have it weighed out and tested at the dealer before I pull her home, and I also will have a test drive with them to make sure it behaves while on the road.