spring relocation

Any idea on pinion angle. That would be the first place to start IMHO. If that is wrong or out of whack, you'll be chasing your tail.

Spring relocation to the frame is a decent idea. To maximize the relocation, you really need to mini-tub it. If you don't want or plan to mini-tub, get the offset shackle kit. The offset kit will get you an inch or so of space, at least to the stock inner wheel well.