ok let me put this in a different format.does any one have 3 lamps linked together "ventillation wise" with a 35-40 foot run of 4 inch ducting.if so what cfm fans are you using.at the moment i have a 10 foot run with 2 600 watts and a 325 cfm. fan pulling the air. before i go ripping everything apart is there a minimum cfm rating for 3 lamps at 40 feet????