DIY Camembert Mold - how big to drill the holes?

[Gerry]

Okay, so I have a bunch of plastic food grade open ended cylinders.  I figure drill some in the sides and I have cheap and easy Camembert molds.  How big can I safely drill the holes?  Are lots of tiny holes better, or lessor larger holes?  I notice the holes look pretty large and few in number on the ones they sell commercially.

[Al Lewis]

3mm