I remember the first backpacking trip I went on when I was exposed to serious rain. No matter what we did we would eventually get wet. There was no dry place to go. Luckily it was also the first backpacking trip that I had my new merino wool clothing. I couldn't believe how warm they stay and quickly they dried. It and a few other things saved the trip.
I have heard Mountain Rescue Teams call polypropylene "shrink wrap" because of how it reacts to flame. Wool has natural flame resistance. A cold weather base layer should be right between loose and snug. Clothes that are too tight don't allow air between your skin and your clothes. It is that air that holds your body heat and allows moisture to wick. a just barely snug silk under a slightly loose merino wool will keep you drier and warmer than any synthetic. I wear layers of wool in the Winter and I never shiver. I have to strip layers to keep from over heating It is better to atart off under dressed and add layers as needed. I set up a level of clothing that would allow me to sleep fairly comfortly at the expected low minus another 10 degrees. With a rudimentary shelter and a fire of course.
The local temps are just about to drop below 0/32 here and today I was reminded that I perspire a lot no matter what I do. Would the Merino wool be the better choice because of that or should I be looking at fabrics differently entirely because of my biology?