I had that exact truck- 2002 crew 4x4 7.3L F250- and here are my thoughts which I recently posted in a similar thread:
Your GVW is 8,800lb. Back then, the ONLY difference between F250s and F350s was the height of the spring block and the presence of an overload spring on the F350. F250s with the "camper pkg," which mine had, got the overload spring.
F350s of that era had a 9,900lb GVW.
IF you have the overload spring and/or you add airbags, I feel that, for that particular model year and truck, you can think of your GVW as 9,900lb and totally get away with it, without (IMO) compromising safety or reliability.
9,900lb GVW minus ~7400lb curb weight = ~2500lb of payload. That's the number I'd work with in shopping for your fiver. Add up what you, the family, and your gear weigh, subtract that from 2500lb, and there's your pin weight limit.