Hoping for some help with venting in my particular design.

If one has a cabinet made out of panda film for the sides and a wood bottom floor and top, what should one use for fans? Should you cut a hole in the top and vent through the wooden top? Secondly, if you want to have passive air coming through sides on the bottom of the cabinet, how do you prevent light from coming through a vent? And what mounts well on panda film? Any help is appreciated, as this is the last piece of the puzzle, everything else seems good to go...light proofing and materials are all set...

p.s. this would be in a 400 watt hps/mh system, and the cabinet is 5x2x5. And during light hours there is a flap that could just be lifted up halfway all day, but don't want to have to do that daily ya know?

Thanks guys.