I think Trich is giving you good advice. I like to keep the vents that are built in for ventilation open because they have filters built in and the other holes that are not in use blocked off. When you are in your 12/12 cycle you will not want all those light leaks, and you might as well get the ventilation dialed in before it's critical. Later on if you are having trouble with too little ventilation you could always buy a photo booth light trap to allow more light in one of those larger holes.