I'm interested in buying Knitpicks Wool of the Andes for a pullover sweater project. I'd like the sweater to be fitted. Can anyone tell me how much "give" 100% wool yarn has? I've never worked with wool before, and I don't know how to choose a pattern size, since I'm not sure if the wool fabric will stretch or be stiffer than the other fibers I've worked with. Can anyone shed some light on working with wool yarn and if you'd size up or down when working with it? Thank you so much for any advice you can give!