fan size for 1000w grow tent???

I did a search and didnt find exactly what i was looking for. Im considering buying either a 3x3x6.5ft or 4x4x6.5ft grow tent. i want to use my 1000w hid light in there. would i need a sealed hood with 6" or 8" ducts and how many cfm would i need to keep the grow room cool. I have 2 265 cfm blowers for air intake and exhaust. The air coming into the grow room would be room temp, about 70 degrees.

they say a good number for air intake is 4-5 times the cubic feet every minute... so if you hooked up one little inline ran that while the lights are on to keep down heat and ran a(what ever your room size is times 5) cfm rated fan you'd be perfect!
so like a 4x4x7 room450-550 cfm is what you'd need so like a 6" or 8" fan. (i like to go bigger like can fan 10" 1100cfm almost) and run a fan speed controller- which also helps save your carbon filter
If you have any more questions post in one of my journals- i never check up on these posts