Make sure when you torque the outer nut down to 250ftlbs like you said, that it isn't so tight that it is grabbing the inner lock-washer and spindle nut and tightening those too....sometimes the tit on the lock-washer winds up in between two threads on the spindle and when you torque that outer nut down real hard it takes the lock washer with it, and the nub there goes onto the spindle, screwing up the threads, and putting a huge amount of excessive preload on the bearings as it also tightens the inner spindle nut.
I did this and it wasn't pretty.....I fried two sets of bearings this way, b/c the half wit that had my truck before galled the spindle threads and everytime I work with the bearings they have a tendency to do the above. Hell I have to check them about once a month because sometimes they will tighten all on their own and preload the bearings.
Just a thought...