hey man sorry i havnt got back to ya sooner... well what do ya know i have the exact same closet space (well mine is 2x3x6) mine is lined with black and clear heavy duty plastic so they will have absolute dark durring the dark cycle. i just got a 400w hps/mh and i have kinda been worried about the heat as well... i dont have any venting put in, theres no way i can get an ac in my window and i am kinda straped for space so i dont think i would be able to make room for a standing ac. all i use is small 6 inch fans i have to circulate and cool air. because i was worried about heat on the 400w i got an 8 inch fan with a clamp, im going to either have this pointing out an outlet hole toward the top of my area or have it right up next to the light. either way ill have outlet holes in the top of the area maybe in 2 spots and then some inlet holes on the bottom, maybe 4 or so. i have my mother and a 6 plant drip tote in my area and i will always have one fan on the ground blowing new air up at my mother and into the room, i will have one fan with my clones in the drip tote to keep them cool and airated and then i will have one fan one the light only and then another pointing out of one of the outlet holes near the top. sorry if im kinda dragging on but i figured since we have the same basic area and problem we could maybe help eachother out. n e way. thats my plan for getting air moving through my area and helping cool my lamp.
think this might help?