I made the 3rd size, so was left with 13 stitches after the crown decreases. So for every one of the 13 stitches I had left, I planned to cast-on 20 stitches using the crochet cast on method into each one, then immediately cast them off again.
Eventually decided that 13 was a dodgy number, so I only made 10, and just purled the remaining 3 stitches together :)
Love this hat SO much ! !