I have tried using only the top airflow and while the flavor wasn't horrible and the airflow was fairly smooth I feel the bottom air has better flavor and I have been using mine with top air completely closed and the bottom airflow 3/4's open. I am really starting to like this thing although it is an unwieldy beast.Did you try closing off the bottom & just using the top airflow? Rip said it's flavorful like that.
Before I forget there is one thing I hate and it's how the base is 25mm and bulges out to 27mm it just looks awkward and it bothers me ......mit