Two here for Heater Body Suit.
I have lived in WI my whole life. Tree stand hunted my whole life. I have tried everything on the list, and the heater body suit is the only thing that works to keep you warm and is reasonable to deal with.
I don't want to start and argument, but I don't like wool because it is heavy, hard to clean, and when you put on a lot, restricts too much movement. The latter is very concerning when climbing and shooting bows from trees.
And a hat (or two at the same time - try it!), a gator, and a hand muff, go with it. You can sit all day like that.