I think you have gotten good responses here, especially from Sadam and White stripe. Optimizing droop will invariably lead to moving either the shackle or the frame hanger. Once you have lifted the truck, the stock mounting points go from being sacred to being a convenience and a compromise. I have cut and moved hangers on two of my cruisers, and have plans to do so on the others as well.
It's all about the droop. I wrote an article about this called the Angle Of The Dangle. Was going to submit it to TLCA for publication. Then I had a huge falling out with them over the raffle truck and just shelved it. I should dig it out and just host it on my website. One of these days.