Grigg,
On the Diamond T, did you see where he said he used the 3500HD spindles on the original Diamond T axle? Did you investigate that as an alternative when you narrowed the axle for your truck? I'm not sure I like the idea of combining old/new parts on something like steering components. They're all engineered to work together. I suppose it could work if everything (spindle mounting surface/angle, bolt pattern, wheel offset, etc.) were perfect--and you were able to find a way to mount the brake calipers. But, then again, he also said he still needed to bend the axle to get the camber right. I just thought that was an interesting approach.
Bob