I've just knitted 3 pairs of what my cousin called really warm kilt socks, He is a wee man with thin legs and wanted them to look chunky for his son's wedding so I knitted him a pair, his son and his grandson, that was my gift to the wedding party, now just a pair for the 5 year old grandson to do......they are delighted with them, I used a double thickness for the calf part using a 6ply wool/nylon blend and 1 strand for the foot, but here the guys wear a pair of ordinary socks under their hose if they want warmth, that usually does the trick especially in boots......