Just hunted tonight for a 4.5 hour sit in 5 degrees and 20 mph winds. Saw 7 deer. Great day in the woods.
Here is what i wore.
cotton boxers, cotton t shirt, 2 pairs of heavy weight rocky thermal tops and bottoms, polyester sweat pants, cheap wool pants. a thick fleece shirt, king of the mountain wool vest, wool shirt, kuiu vest, stocking hat, neck gaiter. 2 pairs of thick socks and baffin titan boots, jersey gloves and a wool handwarmer muff.
I was able to hike the 3/4 of a mile thru 18inches of snow in half those layers and then when at my hunt spot hang my stand in what i wore in. then waited 15 mins for my temps to cool down and added the other layers. comfortable, non sweaty, not cold at all.
Layers are the key! whatever clothing or system you use layers are important. i never belived in the base, mid, outer philosophy. I need more layers than 3! lol.
I also think wind proof layers are important. my kuiu vest and my polyester sweat pants (walmart) are wind resistant. for super windy cold days i will put my rain gear under my outer layer.
I hunt a few days each year that are in the negative temps. bulky stuff wont work. lots of thinner layers work much better. a good face mask and chemical hand warmers are your new best friends.