Looks like I may end up taking a different direction than I originally planned, I might be swapping 2nd gen leaf springs as well. This means I won't be notching the perches like I would when using the 1st gen springs.
Also, I verified that the drive line does in fact need shortened by 2". There is (or atleast on my truck) about 1-3/4" of forward movement in the slip shaft from when the U-joint is mounted to the d70 yoke and then pushed forward as far as it will go. And being the U-joint will sit 2" forward with the d80, it probably won't even mount up without force.