I've drysuit socks fitted to my drysuit which are ~6mm neoprene and use with rockboots. Underneath I've been wearing a pair of thick walking socks. Feet got cold the other day. Any recommendations for a pair of socks to use? I have a pair of the Fourth Element (Arctic?) socks, but not keen on these as they're a bit loose and ruck up a bit when walking. Recommendations for winter socks?