nikerret & Rancher Ed especially, thanks for the advice. Not really what I was asking, but as is often the case the questions you are asking & what you are wanting to isn't actually what need to know. Feel free to let me know if any of my understanding is
DOT regulations (marked DOT numbers, safety gear & a few other things) kick in at 10k (GVWR?), but no CDL. Not really going to avoid this on in the slightest.
CDL is required at 26k GVWR or GCWR with a trailer over 10k (most relevant to me with a 14k trailer, but not relevant as long as I stick with GCWR under 26k).
Trailer GVWR: 14,900
Expected tongue weight: 1,500-2,300
Towing cargo: 1,300 (250 (driver),*300 (tools), 320 (fuel), 350 (30 gal bed tank & tractor fuel))
Total minimum required payload: 3,600 (4.5k would be better for a possible future gooseneck)
Max GVWR of truck to avoid CDL: 11,100
Max curb weight of truck: 7,500
While the GVWR is easy to find published everywhere, the payload & curb weight stuff isn't. Mostly generic numbers (presumably for the lowest trim 2wd single cab & not otherwise clarified).
https://www.ford.com/services/assets/Brochure?make=Ford&model=SuperDuty&year=2017&postalCode=80138 for instance has a nice chart on page 28 with a pile of GVWRs on it for model & cab, but doesn't really indicate what they would match to for engine or other stuff. There is always looking at the door tags, but that's harder to research.
The F250 double cab misses the payload mark by 100-200lbs or so. Depending on weather or not that includes the mythical 150lbs driver & passenger in the for docs much less the extra weight of a diesel or not is probably academic as it's to close to the limit for comfort if you are looking to do things right. I'm not clear if those extra weights are just for the TVTW specs or curb weights either.
https://www.ramtrucks.com/assets/towing_guide/pdf/2017_ram_3500_towing_charts.pdf are a bit nicer matching all the options up. The crew cab 4x4 hemi's look to meet the GVWR & payload constraints, but probably not the Cummins.
Gonna go look at some door labels this weekend to see what numbers show up compared to what looks good.