Interesting, went to several dealers as I'm starting to figure out what I want.
Basically asked the question about how big of a trailer my set up would pull. Tried to get a fill for what numbers people used for cargo weight in the trailer, etc...
At one dealer, they flat didn't seem to know or want to discuss loading.
At the other dealer, they flat said your Yukon XL is rated at 8500-9000 lbs and that is all you needed to know when looking at the dry weight + a hedge for the trailer load. They seemed to discount completely the GCWR number for total weight or the GVWR for vehicle+vehicle load including hitch load. They said that people they dealt with that had "Suburbans" loaded like mine had no problem pulling the 8000 trailers regardless of the other formulas.
Not sure if they are ignorant of all the factors, or just don't want to discourage people from purchasing more than they should. Or if they believe some of the numbers are too conservative.
In any case, I suspect they talk a lot of folks into more trailer than they should be pulling....