Yeah, trying to shop for a soft, light/standard duty spring based on year/model/trim/options will get you no where, and using a stealership will just rip you off. I mean, go for it if you want to, but I think the only thing it will accomplish will be to overcomplicate and waste time. Shop for a soft, light duty leaf spring for an XJ--leave that "99 Classic with SelecTrac" or whatever nonsense behind. OME springs cost about the same as any factory replacement, but I think even the light duty ones might provide a tiny bit of lift. Even if a light duty OME leaf spring happens to give you a little lift in the rear, slap a cheap budget boost on the front to level it out. A tiny boost won't snowball into requiring any special mods, and since you're using 30" tires, you'll be that much safer from rubbing.
If you're really that attached to your Monroes and/or stock ride height--I'm using Monroe Sensas right now; they get the job done, but I'm not terribly impressed by them--get some standard duty Crowns. I haven't seen many factory replacement manufacturers make anything other than heavy duty springs except for Crown. I've seen claims that Crown springs don't last very long though; not sure if that's true or not.
Relocating your shackles for a better shackle angle can also help improve your ride, so you might want to consider doing that along with your leaf spring replacement. It's plenty easy to do.
Build Thread -- http://www.jeepforum.com/forum/f177/whats-chrokeese-build-thread-2525690/