FWIW, here's what I run and they all run with or w/o the cans.

bbl length/cal/make/gas system/buffer

I don't have port dia info.

14.5/5.56/Noveske/carbine/H
runs with either 762-SDN-6 or 556-SD

10.5/5.56/BCM/carbine/H2
runs with either 762-SDN-6 or 556-SD

9/300BO/AAC/pistol/H2
runs with 762-SDN-6


Typically go heavy until it stops running or locking back on last round, then drop one or two weights back light until it runs reliable with various ammo.

I've been lucky that all mine run short or long uppers with nearly any buffer I have at hand.

Whatever works.