duct tape is a wonderful product for lightproofing and connecting tubing. also for the intake vent just put a length of tubing on it with 2 90degree bends. light cant travel around corners. as long as it isn't reflective inside the tubing. if it is paint it black 1st. it's called a light trap, if you don't understand just think of the trap under your sink, same idea. also a 4 1/2 inch comp. fan is not powerfull enough to cool much more than 1 or 2 42 wat cfl's. i originally tried a 4inch fan to exhaust my 350watt cfl cab and the temps were like 115 or higher! i had to switch to a much more powerful fan. just make sure you run it for a day or 2 and watch the temps before you put any plants in there. when i upgraded the fans i switched the 4 1/2 inch fan to intake also.