A hammock sock is like your lawn...you may have a heavy dew, or you may not, and you may have condensation issues. Or not. You can make an educated guess in the evening, but only dawn knows the truth.
My Tyvek sock wasn't a failure, but it wasn't an unqualified success, either. I found that if I vented it enough to control moisture, that warm, moist air rising out of the vent set up a convective loop that pumped cold air in. Yes, it blocked wind, mist, fog, etc, but it failed to create a warmish micro-climate.
Do a search for "hammock socks". You'll find a wealth of good info. Good luck.
Btw, a good source for lightweight canvas is painter's drop cloths.