Just to reiterate, for those that have not checked their air flow, and don't like the high TH:
Make sure that the air hole is positioned so that the incoming air flows perpendicular to the coil, and hits the coil near it's center.
This is likely one of the most frustrating things about these, for many. The shell on these things get the air hole drilled with no regard to where it ends up based upon the particular threadings of the completed unit.
If you bought more than one, and the air holes are off on them when fully tightened, try swapping the covers. They will likely end up with the air holes in completely different locations. I got much better alignment of my two that way. One was perfect, and the other is somewhat close. They were both next to the posts, originally.
The factory o-ring at the base will allow the cover to be backed-off a certain amount to align the hole correctly, and still hold it in place fairly well.
Also, make sure that you keep the coil away from the plastic post insulators. This can be somewhat difficult if you use the holes provided for securing the wire, as they are practically on top of the plastic. My lungs were raw for days because of that mistake.
I've been using mine with the coil attached to the screws on the top of the posts, well away from the insulation, and also more in the airflow, because it sits a bit higher.
The air hole on mine seemed to be 1mm (0.04") in diameter. The smallest tool that I had to try and widen it was a 1/16" (1.6mm) drill, and I used it. This made it super airy on the draw, but further reduced the throat hit. With this, I can either crank the voltage from 4.0 to 4.8 and take the quick draw, or leave the voltage down and slow down my draw myself. It's a bit odd, but workable.
That made for almost 2.5 times the airflow of the original hole, which is a bit extreme. Widening it to around 1.2mm would likely be quite enough, as that should offer almost a 50% increase in airflow.
I like mine even more, now, but hopefully the newer ones address some of these issues. I've heard that they do.