The extra 3/8 turn may not be an issue once in the truck. The spindles should hit the axle stops before the gear box hits it's internal stops. If you have the gears centered, which it looks like you do, when properly adjusted the tight spot should be about center ( 2 turns each way). I would use the tight center as a gauge, and not where it stops. Once on the truck, verify the axle stops are even and the steering wheel is in the center position. If it doesn't drive straight with the wheel correctly centered, find out whats wrong with the linkage, DON'T move the steering wheel.
