There are also products made for scuba diving/snorkeling that are excellent in keeping the mask free of fog. They're inexpensive, maybe something like that would work. I've used the following Sea Gold Anti-Fog and it works well: http://www.scuba.com/scuba-gear-54/028053/McNett-Sea-Gold-Anti-Fog.html
The trick in using this gel is to apply a good layer, then quickly rinse with fresh water, and it leaves a crystal clear film that does not fog.
Also, in a pinch, I've been told that you can simply spit in your mask, rub it around and that will keep it from fogging. Divers swear by that, but I have not tried. Maybe spit on your cam & let us know how it works?
Understanding wind currents and thermals in hilly, broken terrain can often be incredibly frustrating. I've found that collecting and storing milkweed seed pods during the late summer has made me a better hunter in the bluff country that I hunt. These little feather like seed dispersers will float on the lightest of air currents and will show you what the wind is not only doing right at you're location but more importantly down range. I like to use the off season to float them...