Frame of reference-Korea, winter of 1979-80
Today, I'm a Danner Man,
But when I was in the service, I wore a bunch of different boots. Korea, the temps fell to -25 (without the windchill factor). We stood on our aluminum personnel carriers 24/7. The oil wouldn't pour, it was cold.
When I was in, I didn't like the "issue stuff", now that I'm retired, I went back and bought all the issue stuff from surplus stores.
Black "Mickey Mouse" Boots ($35). Wool long-johns, wool pants and shirt under cotton field pants. Mittens with inserts ($20), cold weather parka with linner is $25, Balacalavas are $20. Poncho linner for $25.00.
Polypro and gortex came out in the later years, matterhorn boots were the "cats meow". The weight difference is amazing so I wear my surplus stuff when I'm on my OHV or sitting and the newer stuff when I'm on foot.
As mentioned earlier, layers is the key, if you are going to be moving, strip down before you sweat, as soon as you stop, dawn a dry t shirt and socks. that'll make you feel like a million bucks.
Don't tie your boots too tight when sitting, drink lots of water, no cafine, keep your optics aclimated.
Enjoy your dream hunting trip, send pics.