Thanks User and Kind. Rep to both of you.
While we're on the subject, can anyone suggest how to install a computer fan and cut vent holes while keeping the box light proof? I was thinking of connecting flexible ducting (diameter will be whatever size computer fan I go with) and connecting them to intake and exhaust holes. If both of the exhaust and intake ducts make one loop (3 feet or so), will that effectively prevent light leaks? I'm thinking two passive intake lines, both the diameter of the computer fan each making a loop. The computer fan will be mounted on the inside and push the air out of the exhaust duct, which will also make a loop.
Will this work? Only issue I can see is too much strain on the computer fan.