You got the assembly order right.
In your hunt for lug nuts let me know if you find US made ones. I ordered some Dorman brand from NAPA and they're Taiwanese, and no other options available from NAPA. I'll return them if I find better ones.

I'll look for numbers on those axle saddles.

I have some single wheel 13x3.5" drums, need to check if they fit in the 19.5 dual wheels, I think they might. By swapping them and spacing the backing plate out you'd gain about 1.25" room at the springs. I was going to do this for single wheels any how but might also work with duals.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-