Knit from the top-down.
Increased to 78 sts only (larger gauge).
Started the ribbing after 13 cm. Knit in 1k2p ribbing until the skein ran out. I think the size is just right.
Did not knit a turning row, so that he can fold the hat wherever he wants.

It is snug on him, which is a first for me. My head is so large that I always have trouble figuring his size.