I got started on my rear mounts. I made them out of the same 3 1/2" square tube that I made the fronts. The rearend is 40" between spring perch centers, so I used some scrap flat bar, and made a jig that holds the mounts level and the right width apart. That way I can square and level the whole thing as one unit.
Once I got them clamped where I wanted them, I started building the hangers.
I still need to make a few more braces, and final weld everything, and I want to take a few more measurements so the truck doesn't crab walk on me.