If your gonna 4 link, do your research. I have been playing with the Idea of a 3link F / 4link R set up for my YJ for a while, just not ready to back half it yet (not that you have to)
I say do it and take plenty of pictures. consider Solid Works for a cad program to design the link set up.
Or
Polyperformance has a weld on 4 link stretch kit, not cheap, but all the hard engineering work is done for you