I did have a pair of all leather boots (Silvis I think) 5-6 years ago, and I recall my feet getting very wet from sweat. Even though it was cold out and the ground was covered in snow. Appreciate the comment on the Kenetreks. My feet might be worse off if they are exceptionally damp, than if using the uninsulated boot that potentially breathes better. I am going to give the silk liner + expedition weight wool sock routine a try. Worst case, I can always put some toe warmers on.