
Since I'd never done any corrugating ribbing before, I searched the web for info. Here are my adventures in making the hat:
First comes the supposed problem with curling and with strands peeking out from the edge. After a few attempts, I ended up with a knitted cast on (though a single cast on would work as well, and also, I suppose, a cable one).
Then, more importantly (to prevent curling), I did one round in k1p1 ribbing with the same color -- dark gray.

I used Patons Classic Wool Merino and size 7 needles. There is no problem whatsoever with curling and my DD has a nice warm stylish hat.