My winter beanie is too big to fit in my helmet (already at the max size for my big head). I haven't tried a skullcap yet and maybe that's the best option. I tried a Buff which is this thin microfiber tube you can wear in a bunch of different ways... I usually do something like this


This fits find in the helmet and is ok, especially for my cheeks, but my head gets pretty cold in freezing temperatures. What solutions are you using in this cold weather along with your heavily vented helmet?