So I have a friend giving away the item in the pic I have attached so I'm going to try to make something like you've done just for the hell of it. Have a full roll of Mylar film and 2 Mars 300 lights (will just use 1) and I'm going to try to make my own stealth grow box. Once I get going I'll either post here or create my own post...this should be fun!! Thanks for all the tips and tricks here!!
Well it looks like it worked out real good for you. A bit of this for your efforts.What the little flower things on either side of the plants?
Good choice. Not too powerful a strain. A fruity Northern Lights buzz. Heads Up. The strain can get some funky leaf curl in veg and throughout the entire grow. No need to worry....Just let them ride. Seems to be normal for this MG strain.
Throw the 6" exhaust fan in. Better to have better negative pressure. My armoire doors will close themselves when the MAX 6" is on #2 (of 3 speeds). Is there a speed control? If not no biggie.
Air circulation is key. A 6" exhaust and an intake holes of twice the size as the exhaust is all that's needed. I added a 12" floor register cover from a hardware store for my intake. It's louvered so I can adjust the intake air. I have wide open anyway. I'd try that before adding more electronics (4" intake fan) that may not be needed. The more the air circulates it will eliminate many issues as mold for instance. Think of a breezy spring day. That's what you want in "VEG" and a breezy autumn day in FLOWER. The 6" oscillating fan is perfect as long it's breezy and not at a gale force wind. Mimic the outdoors inside. Even the room that the cabinet is in needs to be open to air. Normal room environment should be more than adequate.
Enjoy your new grow room. You'll be very pleased and I am impressed. It really feels good to be able to throw an idea out and see someone take it and do it. That's America. 
