I centered the pitman arm on the sector shaft, measured its distance of travel in both directions and then torqued it to 100 lbs. My 1950 Buick shop manual made no mention of removing a washer when taking off the pitman arm, so I surmised there shouldn’t be one. My torque wrench only goes to 100 lbs., and the manual said 100 to 110 lbs, so that choice was easy to make. After equalizing the length of the tie rod end, the steering wheel is centered nicely. Job is done, and it went well.