my winter commutes have been anywhere from 4 F to 40F this winter. I use a sixsixone helmet that is multisport so more coverage. I wear glasses and have cold air induced asthma so I use a multitude of beanies and face masks depending on weather, in extreme cold I go with an Adidas thin fleece beanie that goes low to cover ears and has a brim and my fleece bandanna that covers up to eyes and down to chest, it velcros around back of head. I also keep padding in helmet thin so I can wear what I want on my head, thick or thin.
When I run I have a full face and head balcava with neopreen in the nose mouth area so no dripping or freeze back, its pretty thin too and I run before I go to work so its just as cold.
Your best bet is to hit REI or someother store like it with your helmet and start trying things on.
And dont tape the vents, thats just well I dont want to put anyone down so just dont.