Practical tow capacities not the extremes or limits?

I would probably go with the 6.0 for a couple of reasons. First, I wouldn't want a truck owned by 6 different people, was maintenance preformed, records? Second, your not towing at max weight, while the 6.0 won't pull as well as the 8.1 it will do fine and will get better mileage when driving unloaded. Is this you Daily driver as well? Third, I always prefer a 4 wheel drive vehicle....better to have and not need than to need and not have.