I have 100, 150, 200 and 230 or maybe it's 250 can't remember as Icebreaker used different number than Smartwool and I have both. The heaviest I use if I am in SUPER cold conditions in one of my kayaks with my dry suit on. Other wise I use the 100-150 stuff for walking around in. I usually wear the T-shirt tops with a shirt. If the temps drop then on goes the long sleeve top over the T. If temps drop more then off go pants and on go long johns. I carry this gear with me as it is light and take no space. I gave away most of my Patagonia poly-pro gear as it had zero worth to me once I started going retro (using wool again).
BTW I look for WWII wool field pants. Have one pair that are about one or two sizes to big but I use them and another that are fitted just right. Only problem with the field pants is they pick up a lot of tag along plant stickers, but they are WARM as heck.