As promised earlier, my closet pics for ideas.
The closet;
Door open / gate down;
Bottom view with fan (blows in)
Top (open exhaust, like a power vented stove pipe)
Bottom w/ gate up
Latch to hold gate up. Actually a double headed nail, with a compression spring counterbored for retraction and used a wine cork for a knob. A 2 X 3 ripped lengthwise makes for the inner rails of gate's slide. Held with 4 screws each side. Didn't want to paint door with reflective paint so inside slide is. Also with gate down and lower fans on it's like a power vent. Works good. (IMHO)
My 250 is vented. I simply used a cheap 4" fan with the bracket removed. Some extra foam from door seal made it fit perfectly.
However, it's noisier than I like. Not all that much is needed. Just want to keep the heat rising (another power vent thing). When this grow is done, there is a 120cm PC fan going in the hood with a speed controler. These cheap fans don't like a speed control (I know, I tried, they cook).
That's basicly it and the way I run it in veg and early flower. When the smell starts I turn on the blower that is vented to the basement through a large scrubber. Also on a speed control. I went way overkill on the CFMs. I'm able to draw cool air from the basement or warmer air under the door. Both make for a negative presure and lets the adjusted blower maintain a degree of temperature control.
Light is a 250 w DIGITAL and will burn MH or HPS. I've the ballast in the cellar, but it runs plenty cool enough so you could put it in the closet (up high) with no ill effects.
I know my electrical plumbing looks like shit. This is a test grow and will be cleaned up after this grow.
Maybe something here will give you a useful idea?
PS; While this is a legal grow, I still try and maintain some stealth. Very few know I have a card and want to keep it that way. Just eliminates the hassels I hear others getting into like friends want some, people want to see (and talk), someone attempting to help themselves when nobody is home, etc. I like a low profile, and the state appreciates not having issues with MMP/Cs.