I have had various combinations on the front and back and my favorites so far are........
REAR: A complete XJ spring with one extra main leaf added, 5 leaves total (clearanced the big end of the extra leaf to fit over the small end of the other, makes a military wrap, you'll have to redrill the center pin and cut off the small end of the added leaf). It is possible that I may add one more leaf to this pack in the future.
Front: A complete XJ spring with one extra main leaf, an extra second leaf (next largest) and an extra third leaf, 7 leaves total, same procedure for the main leaf as mentioned above and I just stacked the other leafs. I think I'm going to take my front back out and cut the extra leafs down some to tier the leaf pack instead of having the one stacked ontop of the other end to end.....does that make sense? More cosmetic for me than anything.
XJ leaves are super soft, so some of you may cringe at the thought of 7 leaves in the front. Don't worry they are no means harsh and they flex awesome. I do use two clamps on each spring on the first clamp hole from the center pin (there is a whole on the leaves where the factoery clamps where, helps make them stay put)
I've heard of guys wrapping XJ leaves and having all sorts of trouble from them, I'm not sure if their using an unmodified pack or not, but I've been wheeling mine for some time now with no anti-wrap bar and havent had any issues. I have bent a rear spring just to the front of my right spring perch but it was on a set of spring packs that I removed the shortest leaf from (I thought it would flex out better) but realized that it made NO difference on the flex but it did take away alot of support from the spring packs.
I did run my front springs built the same as my current rears and it was WAY too soft. They almost de-arched just from the weight of the Jeep.
I'm curious as to what combination of leaves others have used, please post up and tell us.