There appears to be mixed sentiment on recommended footwear to be worn between your feet and your winter cycling boots.
On the one hand is the camp that says at least two pair of socks, with variations such as using chemical packets called "toe warmers" ... to be worn between the first and second pair of socks.
On the other hand is the camp that says if the winter cycling boots are truly insulated winter boots, then only one pair of socks is needed between your feet and the winter cyclying boots.
The reason I ask is that it would make a difference on what size of winter boots to get ... as far as wearing one pair of socks versus two pair (and possibly additional warming accessories).
Personally, for January Michigan winters, I would probably join the first camp, but then I've never used winter boots under any brutal winter temperatures yet.
It would help us to know what the gang wears on their feet ... with their winter boots ... so I can get an idea of the different insulating styles. Also ... what temperatures they ride at ... that determines what they use with their winter boots.