need help determining fan size

planning on air-cooling 2 xtrasun hoods with each running 1000watts each, the airduct will run 12+ feet (length of room) ,going to put a high powered fan at one end to pull fresh "cooler" air through the hoods and out of flowering room,
will a Centrifugal fan with a rating of 435 cfms' be powerful enough to vent all the heat coming off the 2 lights? and vent it out of the room?

http://www.phreshfilter.com/selector.php kinda helps with cfms
when in doubt get a bigger fan and a speed controll or a thermostat to run the fan

How bigs your room?

A 6" fan should work just fine as long as you don't have too many bends or 90 degree angles in your ducting.

Proper ventilation guide

Since you're only exhausting the cooltubes on your lights you just need to figure out the cubic feet contained inside your vent, which is ridiculously small. 400+ CFM should do the trick very well.

thanks for the quick reply, information is greatly appreciated