I built a 2 meter square smoker with an offset firebox roughly one-third the space. I have a chimney that is roughly 9 inch diameter exiting the smoker and making a left hand turn to vent outside. All of this chiumney is 9 inch dismeter. Then outside I am reducing to 5 inch diameter and venting vertical 45 feet or so...can anybody tell me what is going to happen? Should my vent pipe be larger?