0.081" should run the gun on any decent ammo. I went 0.085" on one I was working on, just in case any ammo was needed, even inexpensive steel-cased foreign ammo.
Now, the other side of that mentality - you can run 0.085" just fine on yours, based on the adjustable gas block you're gonna use. Go Big or Go Home!... Drill it to the 0.085" and if you want to tame it down, you have that capability through the adjustable gas block. Justmake sure you realize this right now - brand new build, brand new parts need to carbon-seal, through carbon fouling. Run the AGB in the wide open setting while you're breaking in the gun, and letting the carbon fouling seal the gas block-to-barrel, and gas-tube-to-gas-block.