I believe you about the shackle lowering the highth, but I've got go look at it again, I can't get a mental pic.
I went to 1 of the sites (diy4x) that you listed and I'm going to have about $152 in doing it this way and that doesn't include shipping. Thinking about how much that will cost and the additional labor to do it a second time when I change the brackets and the cost of the brackets and bushings, I think that I'm better off in the long run to do the brackets to begin with. I don't remember the measurements on the one that I'm thinking of, but I think that it's got enough adjustment to give me what I want. It will cost a little more, but I only buy the parts once and install once.
Thanks for getting me to look at that, Paul
Measure six times, cut twice...