Even with the air holes drilled drilled out massively you are still restricted to about a 1.25 mm airhole thru the 510 center pin.Most tootle-puffers DON'T want more airflow, since you can't MtL hit with too much air. I'm thinking those who're drilling out their clearos need to report to the modwompers thread ASAP.
Heck, I hang in there just because I'm a coil-builder; I'll never be other than a tootler in terms of airflow -- MtL for me, ALWAYS. I'm trying to stay free of smoking, not huffing.
Andria
The threadind on some batteries blocks some of the base airholes and drilling them out helps with this.