Spot on mate...lol..but serious, Blink has it "dead nutz" Well..the fan can be a 200cfm, way plenty if you plan to run one HID. I bought an Eclipse fan 4in and mounted it to a 6" cool tube and a 4" Elf on the back end. I tried every combo I can think of and this IMO hands down is the most effective way to control the heat/odor in that box and yours is even deeper than mine. Even going through the carbon filter, this thing still puts air out the other end like a frigg'in leaf blower. I first bought a 6" to fit the tube and that some bish will damn near blow ur cabinet over..630cfm. Instead I just had to come up with an ingenious way to join them without reducers. I have pics in "hydro" under "Cabinet pics...finally" If you have an attic you could run the exhaust up through the ceiling, that would be CHAMP cause that much air moving still makes alot of noise if you just put it out the cab into the closet. Also would heat your intake air. CO2 helps ALOT, you can buy the emitter kit fair priced on the net and a welding gas supplier caries the gas. Gradual bending into a SOG or a few small bushes..you choose. I just did SOG but my next I planned to do a few bushes in DWC instead. All element for a grow is maintained than that space wil most def yield quality green.