The fleece balaclava I bought from Terry fits snugly, as it is woman specific and I think came in sizes. Unfortunately, even when I need it to ride down my hill at 30 degrees at 5:30 AM, I get sweaty and overheated as soon as I start the rest of the ride. So, I bought a lighter weight Craft balaclava that DH has. It's a one size fits all and it is big on me. The top of the head part comes down pretty far, so I have to sort of re-arrange it in the back. The head part does feel loose; it did help with ventilation, but I don't want the freezing air coming in too much.
Try wearing your glasses on the outside of your head cover. They do stay on. It prevents cold air getting in. Doesn't help with the fogging so much, but it does keep you comfortable. Even using the Cat Crap stuff doesn't prevent my glasses from fogging. If I am riding in the dark, I usually end up taking my clear glasses off, near the end of the ride, as I can't stand the fogging.