Do you use a ridge line on your hammock? If you use a RL on the hammock, in the cold weather, you can use a poncho liner, a fleece blanket, about anything will work to some extent, to cover yourself by laying over the RL and sides of the hammock from end to end to cover yu with and as long as its somewhat breathable, you might avoid condensation and add a few degrees of warmth also. Something you might try if you don't have a sock or a cover..experiment that way also with different gear.