I bound off my navy cowl! And promptly discovered that it was bigger around than I thought it was, which means I probably should have gone ahead and used the second ball of yarn in it. 
It’s hard to tell how big something will be when it’s scrunched up on circulars. And, of course, doing a stitch count and the necessary math would have just been overkill.
So, now it’s big enough to go up over my head like most enormous cowls (instead of the neckwarmer I thought it would be) but it’s not wide enough to do more than make a feint at keeping the top of my head warm. Perhaps I can knit the second ball into a similar size, then graft them together down the middle. I’m also hoping that the minor stretch job I gave it while blocking will help it expand.