I did some checking on the Ford website and here's their limits for the F350 DRW 172" WB 6.7L diesel receiver. This is the limits for the actual 2.5" receiver mounted under your truck, not the truck's capacities...
F-350 Super Duty DRW w/6.7L engine and F-450 Super Duty (weight carrying capacity) 8,500 (Weight carrying tongue weight) 850
(Weight distributed capacity)19,000(3)(5) (Weight distributed tongue weight)1,900(3)(5)
Here's the website:
http://www.fleet.ford.com/resources/...tyPU_Sep28.pdf
So, the way I read Ford's data, without a WD hitch you're limited to 850 tongue weight and 8500 max trailer weight. They don't address sway control, but I wouldn't tow anything longer than about 25' without sway control of some kind.
ADDED: I can't remember where I read it (da*m CRS) but the above data on weight restrictions for the receiver are when used with a solid 2.5" hitch bar. If you use the reducer and a 2" hitch bar the maximums are restricted, but I can't remember by how much and can't find the doggone information right now. But, anyway, the point is that if you use your 2" hitch, the maximums are somewhat less than the 1900/19000 ratings that are listed above. How much less??? I don't know.
ADDED#2: Found it. It's in a footnote in that same reference. If the 2.5:2" adapter is used, the maximum trailer weight is reduced to 12500 and the maximum tongue weight is reduced to 1250. WHEW I knew I'd seen it somewhere.... LOL