Stocking stitch hat knitted more or less freestyle on 3 mm dpns, out of ggh superwash 100% wool yarn, trimmed with ggh Mystik in seed stitch. I used the kitty hat in Stitch and Bitch as a rough guide, but merrily adapted it myself for skinnier wool. This was before I learned to ssk: hence, the crown decreases make a spiral shape, as they are all k2togs.
Verdict: hats in dk yarn are not warm enough. But I learned!