I did try searching so I apologize if this has been discussed already.

Background: I am building a 300blk AR based on a Larue or as much as possible Larue upper.  I have a Larue 14.5 barrel that I'm going to have cut down to 9", it is drilled for a pistol length gas system, (it is 1:8 if that matters).

Question: for the gas block, in a perfect world I'd just order Larue's gas block and not think about it but I do plan to shoot at least a healthy amount of subs if not mostly subs so I want to make sure it will function properly.

If I'm being stupid and putting too much thought into the gas block when it is more the BCG that I should worry about please let me know that too.  

Thank you!

Depending on your loads you may need an adjustable gas block, otherwise I doubt that it matters.  Just make sure it fits under the handguard.

^ yep. Adjustable if you need. I set mine up for use with my can and then never touched it again. So YMMV.

As for BCG, a basic 5.56 one will work just fine. I opted for the Nickel Boron on mine so it stood out as being different.

Appreciate the quick replies, thank you!

I've got a 10.5" Noveske barrel. Geissele gas block. Pistol length. BCG is a Noveske as well. Spikes Tactical H2 tungsten buffer. I forget what the spring is. But, it's nothing special. Just a standard carbine spring.

It shoots subs and supers just fine.

+1 for a BCG with a good finish.

I got the DLC on mine. Cleaning it is super easy.

Shooting subs suppressed gets pretty dirty.

You can alway run an adjustable bolt carrier
and a standard gas block

https://primaryandsecondary.com/gear-review-bootleg-adjustable-bolt-carrier/