I have my sami set up SPOA with YJ springs. I had enough room for 34" LTBs, with my bump stops in there is no rubbing.
As for finding some YJs i would recommend buying/finding a set of beat on springs. I got my from a buddy and they were negatively arched and looking pretty worn out. When i slapped them under my samurai they hold a positive arch and are super flexy. (Im pretty sure there not going to settle any more)
I would stay away from shackle lifting, unless your just doing some fine tuning, such as leveling out your rig. The bigger your shackle gets the worse your shackle angle is.
Sounds like you have a pretty good idea of what your going to be doing. Get to getting and let us know how its going!
Hope that helps some what
Amilla