If I take the Armada as an example, I think we would meet all of the limits in the specs, at least number-wise. It's things like sway on the highway and bogging down going up a hill that I'm worried about, and stories from actual users are the only way I can find out about those issues. For numbers:
TT dry weight = 6400 lbs.
TT fully loaded with my stuff = 7400 lbs.
TT dry tongue = 701 lbs.
TT tongue + hitch = 800 lbs.
2012 Armada SL 4WD (example car) towing capacity = 9000 lbs (>7400 lbs)
Curb weight = 5732
Vehicle weight + family + stuff = ~6300 lbs.
GVWR = 7150 (>6300 lbs)
Max tongue = 910 lbs. (>800 lbs)
Numbers-wise, everything looks okay to me. I think I would find similar results with the other three vehicles. The "too much sail" comment is what worries me, but again I point specifically to the successful stories from Armada owners with good WD/ anti-sway hitches (and not so much owners of Tahoes and Expeditions).
Otherwise, I'll have to convince my wife to buy another truck... Cuz my Frontier definitely won't cut it...
