Heard from a guy I know who's a gunfighter for a living about how he runs a sling on his carbine and why, and why my set up was for flat range work. So, being the pragmatist I am, I had to give it another look. Basically, I've moved my sling from a "wide" set up to a "tight" one.
The main reason for moving the sling in tight is that it makes the rifle faster and handier to move around. It allows the end of the rail to be "clean" so you can move stuff around if needs be. I only run a light and I don't have a 12" rail...yet...so I don't think I'll be moving my light, nor will I be putting an X300 at the 12:00, because I can't. Not sure I would anyway because of the switchology, but that's a separate post. Another reason to sling in tight is that if you have to crank down on the sling to climb a wall or something like that (Yeah, sure...I'll climb a wall. It could happen. *rolling eyes*) the sling is less likely to slide off your body. Not so much a factor for me, probably, but that's a serious consideration for some people so it bears mention. This set up keeps the sling off your gear more than slinging wide does, too.
The downside? The rifle is less stable on the sling, and takes a bit more adjusting to get the length right. I'm still fooling with mine; I think it's a little bit long still. It's kinda nitpicking a little, but the rifle feels "heavier" on the sling. The weight's concentrated more, so physics still work. I gotta put in some more time with it, but I think the advantages outweigh the disadvantages.