Trying to narrow in the clothes I want to bring for a two week backpacking trip, and I'm wondering if wool will play a part or not. It can't be beat in terms of thermal value in both cold and warm weather, but it's not the lightest option. Synthetic sports shirts like from Under Armour breath better and weigh half that of wool. The temperature range will be 60-70 during the day, and 30-40 during the night.

Should I forgo the wool and opt for lighter synthetics? I'll already be wearing a long sleeved hiking shirt, and have my packable down jacket if I need a third layer.