Grendel Upper: Oversized or standard barrel extension tunnel

[Darryle]

I have several Aero XL uppers and several BCM uppers in the safe. I am building around the Liberty 16" medium weight fluted barrel and I want to squeeze every bit of accuracy I can out of this build. Do I use the BCM because of their thermal fit or do I truck on and build the Grendel like I did the 6mm ARC on the Aero XL upper and bed the extension with Loctite 620?

Thanks