Deckard,
degreeszero has listed a forum that's quoted the article I read. I don't recall where I read it. It was during the time I was trying to pick between the DPMS and Armalite. I went with the DPMS (The Armalite came after and only because it was unique).
degreeszero,
It's the standard space in any AR rifle. Depends on how thick the gloves you're shooting are. That being said, shooting with gloves sucks. I've only had a few pairs that were ok. It also depends on how cold you want to go. I personally recommend going inside and shooting .22LR during cold winters. I've shot in -30 and it really wasn't much fun. Shortest range trip ever. Hands, feet and ears. Always the first to hurt. By the way I hate the cold.