I'm using a basic MIG welder and have a through the wall 24" square exhaust fan rated at 1,075 CFM about 10' to 15' from my welding table. I still smell fumes for about a minute after welding (I'm usually close to the work area since I weld very small things). Do I need to get an overhead hood (only about 10' ceiling with offices above me - can't go through the ceiling), or maybe just a flexible duct (with or without an inline exhaust fan) with a little hood that I can move directly over the active area connected to existing wall fan? What size exhaust in line fan (if I need this in addition to the wall exhaust fan or that would be overkill)? What size ducting - can I just use dryer vent ducting?