I tried the forced fan exhaust I have a 8 inch stack and installed a 4 inch elbow in it just above the super sucker hood that would blow straight up inside the stack. I hooked up a fan from a clothes dryer to it. The fan blows like crazy. I thought it would create a low pressure inside the hood drawing smoke into it. It kinda worked but results were disappointing. I removed it,plugged the hole and it works even better now. And yes, I had a door open for makeup air too. The idea of forcing air into the work space would have to work because the air going in has to go out the path of least resistance(chimney)