This is a technique for setting up a standard bowl that the guy at my local shop taught me. It's fairly simply and works surprisingly well. Even without a phunnel bowl, you can experience rich, full flavor all the way through a set of coals and probably half way through a second set as well. This works by restricting the flow of juices from the bowl, thereby extending the flavor. Of course, as with any different technique, you'll have to give it a little finesse to get things just the way you like them.