I just signed on with Jake Jefferson for an interior grizzly hunt. I could have just asked Jake what he uses for his base layer but he is in far better condition than I so it would be like comparing apples and oranges. I have many different types of long underwear and assorted base layer combos but I want to know what the experts wear----the experts that will soon be 61 years old. My heart is much bigger than my gut and I will go as far as I must but I will surely sweat gallons!!! Please share your choices with me. It`s a May hunt in the Talkeeta Mts. THANKS!!!!!