We have a 2003 Yukon XL 4x4 Quadrasteer, 6.0L engine, 4.10 gears(9300lb rating). Our TT is 35.5 feet hitch to bumper, plus a few feet for a cargo rack. Mfg spec is 7600lb dry weight. Previous to this we towed a 22' tt with no slidouts, around 4500lbs dry. With 3 kids and two dogs it was no fun in the rain! The larger camper with separate bunk room for the kids and 2 slideouts has been great.
I would not want to tow a heavier tt with our Yukon, but the 8.1 engine with 4.10 gears (1200lb rating) I think would be ok for either of the campers you are looking at. I recommend a heavy duty transmission cooler in whatever vehicle you decide on. Also, those tongue weight ratings you posted are for a weight distributing hitch, those numbers are much lower without. (Just making sure you know).
Another option would be a used shuttle bus. The dually rear end would be very stable towing a tt, a diesel would be great, and there would be plenty of room for everyone. You could even put in a jacknife sofa or sofa sleeper if your tt did not have enough beds.
Please let us know what you decide.
