I really don't know where some folks get their "average" or "typical" weights for cargo from. The only way to know for sure is to weigh your TT when you get it new and again when you fully load it up for camping. I did just that when we got our 3rd TT new.
It weighed 190 lbs more than the factory dry weight due to options that we ordered. (KZ defines their dry weights as the rolling average weight for each model.)
The weight of all modifications was 119 lbs which included things like suspension mods, 2nd TV in bedroom, 4-stage water filtration (under sink), WDH snap-up brackets & DC cam arms, built-in vacuum & more.
The weight of all cargo for two adults came to only 555 lbs. We transferred ALL of our cargo over from our previous TT of the same length and layout (identical make/model TT) so nothing was left out. Cargo included all the usual stuff like BBQ, campfire in a can, sewer stuff, camping chairs, spare 30 amp cord, kitchen dishes/utensils/appliances/food, bedding, bathroom stuff, books, DVDs, tools, spare bits & pieces, blah, blah, blah.
The total of everything added on top of the factory UVW came to only 674 lbs. Far short of numbers like, 1000, 1200 or 1500 lbs. Some folks of course may load more "stuff" than most others, but the normal sort of CCC number for two adults IMO would be well under 1,000 lbs.
Holding tank contents would be in addition to UVW numbers. CCC numbers can vary a lot from say around 1K lbs to 3K lbs. You can't trust factory CCC numbers either. Just one full holding tank would put us over our GVWR. A higher CCC is a good idea and may also indicate a stronger frame.
Note that for towing a TT, the payload capacity of the tow vehicle is the important number, not "towing capacity". I recommend taking your TV to a scale with a full tank of fuel and loaded up as you would for a camping trip (including all pets & passengers) and then subtract that from the GVWR on the door pillar sticker. That way you will have an exact number to go by and have left over for the tongue weight of a TT.
