Trying to make an informed decision on buying heavyweight 100% virgin merino wool longjohns for warmth. What I'm running into is confusion. I'm looking at Minus 33 95$ mens 100% wool expedition weight bottoms and Filson 105$ Alaskan longjohn heavyweight 100% wool pants (longjohns). There are more companies that sell wool longjohns but these are just a few that sell heavyweight wool longjohns. How to compare? What one question can I email the different companies to find out if theirs would be warmer than others? material weight maybe? or some other question ? Does anybody KNOW about comparing 100% merino wool fabric by numbers for warmth as opposed to this or that works for me?