I'm working on a different hat. I pulled two 50% wool / 50% cotton skeins from the stash for this project. I'm just not sure the yarn will offer enough stretch, and more importantly, recovery for this hat. But I'm going to finish it and see what happens. The yarn is wonderfully soft, but it might be a bit too drapy. This is a new pattern for me too; it's easy and goes rather quickly. Every four rows you offset (or move) the K2,P2 rib by one stitch.