So, size large of this pattern hooked with a 4 mm hook fits my enormous head perfectly. Great for me, but that would mean this size would be too large for most people (I can hardly ever find hats to fit!). I would definitely make this size again for myself, but next time I’ll try it with a 3.75 mm hook, just to see if the fabric might be a little stiffer.

I found this celtic knot chart through Pinterest, linked to here.