Of all the adjustments I did on my WD I never had a torque wrench. A good 1/2" breaker bar and a 3' piece of pipe for a cheater bar will work. I would replace the lock washer though if it gets used too many times.
FWIW I never used a torque wrench on my 5'er king pin either. I just welded a socket to the end of a 3' pipe and gave it all I've got. 5000 miles later and it hasn't moved at all. I scribed some marks on it to see if I would get any movement. Nada. A 3' cheater bar will generate a lot of leverage. Same as a regular 1/2" ratchet to a 1/2" breaker bar. Way more leverage.
