I had problems with my phunnel for awhile until i worked out a technique. I use a homemade scalli mod (remade every few bowls as it does get a little dirty) made by wrapping a thick square of aluminum foil over a water bottle cap. It takes a little practice to get the airflow right with the mod, so don't get discouraged. With the mod in place sprinkle your shisha around loosely as you would with an egyptian bowl, test the airflow by sucking the bottom, and foil it. As for the holes in the foil, most people would recommend concentric circles, but that doesn't seem to work for me. Instead i use a hole pattern like the one below: (forgive the poor artistic skills-i threw it together in about 30 seconds)
Moving coals and adding/removing a windcover makes heat management fairly simple. Hope i could be of assistance.
Edit: i usually use 2 CH instant lights.