I've been using my uninsulated Beartooths for the past three years for all weather conditions. But my feet do get cold when it gets down into the teens, especially when there is snow. I will use my pac boots but for longer hikes they are just heavy. Do you guys think sizing up and getting a 200gram thinsulate Beartooth with heavier socks will do the trick, or should I look at alternatives? Thx Pete