I'm looking for a thinner keymod rail section. I currently have a Noveske, but it hangs my light way off to the side, and I'd like it to be a little closer to the rail. Anybody know if the BCM sections are thinner? Or if anybody else has some that are?

What kind of light are you running? If it is a scout type, might be better off buying a keymod scout mount.

yeah see if there are any keymod mounts compatible with your light. That would be the best way to go imo.

I'm running an X300 Ultra. Not really a fan of the scout type lights.

Gotcha, and I have not seen any specific mounts for those like the scout lights. Question though, how thick is the Noveske rail section? I have not used theirs, and I have a BCM one I can try measuring when I get off work.

I love the BCM KMRs. The inside diameter is 1.3", outside is 1.5. They're not cheap but they are very slim and have a great, tight lock-up. A friend and I collaborated on a two rifle build. We used their 20" SS410 Upper on one and on the other we loved the KMR so much we replaced the other handguard with it. Also it feels great with the rail panel kits. They help get rid of the cold, uncomfortable metal feeling.
Here's the 13". It's not cheap, but it's worth it.
http://www.bravocompanyusa.com/BCM-KMR13-Free-Float-Handguard-p/bcm-kmr-13-556-blk.htm

I doubt there will be much if any difference across brands for a thinner profile rail as they have to meet the minimum specs for them to be able to interface with variety of different attachments.