Yeah, that's it...if you went from 3/4" to 1.5" BS clearance, its sagging all right....a lot.
You sound like you've got a lot of weight on there....which is my problem.....
I went to a set of 300M 28.5 mm t-bars...tough freekin metal, gives a freerer range of motion w/o harshness, and ccan hold of the 500 or so lb of armor, winch/bumpers, etc....tools, OBA, and so forth I haul around in my never ending support of the gasoline industry.
I put them in almost 2 years ago, and haven't had to adjust them yet, let alone re-index.
So - to clarify...It sounds like you are asking - if the front sags, are people using shackles and or AAL to bring the rear up if it is sagging too?
What ever combo you choose, remember the X is designed to run with a slightly nose down attitude, so some "sag" is just normal up front...but not as much as you're describing.
As for a fix for a saggy butt....shackles can't sag/are sag proof, but don'y raise the load carrying capacity, just lift you, and give you better articulation.
AAL's are going to sag under load, but do slightly raise the load carrying capacity, but, do hurt your articulation.
So - if your butt is sagging now, you are overloading the leaf pack, and an AAL can help....do you still have the load leaf in?
I left mine in, even though it hinders off road clearance a lot, just because of the loads I carry, especialy heavy equipment into the boonies for work....and spare parts, tools, etc...just to play.
So - Flesh out what you want to accomplish...and we'll see what would work.