Notice this on gable vents and fans:
BlockTheHeat.com -Attic Ventilation Problems You would need to drill every rafter bay with 3 holes each to get close to the required air supply. I would use this:
Cor-A-Vent : IN-Vent Block the other gable vent closed. Seal all air penetrations to attic from conditioned air space, including fan and light fixture holes. Leave any gas unit flues alone.
A good read:
Audel Complete Building Construction - Google Books Be safe, G