Gunsmithing What size gas hole for pistol 6.8?

[LibertyArms]

Ran into a bind. First pistol length SBR im doing in 6.8 SPC, The barrel came with a .060 hole. Wont chamber the next round. Anyone who is doing these let me know what hole dia. your going ttherwise i will start small and work up lol. I have found very little info on this. i have a heavy buffer in it, and is in an auto lower for a PD. will not be suppressed, and running 115 otm SSA ammo.

Thanks