Shouldn't have to tighten up the airflow, try posting some pics of the coil with the cotton you have on it... for some reason I'm thinking it's the amount of wick that you're using. Always use just enough to reach the deck, and in your case I wouldn't use much more than that... are you sure that the coil isn't choking the wick? That would explain the dry hits imo... it's hard to tell what you're looking at :/