I decided to add a glengarry to my collection and was curious whether it was practical. Wore it on two days hiking the Gettysburg battlefield and camping. Quite cold and windy with substantial wind gusts. It did a wonderful job of keeping my head warm, though no protection from sun glare. After a while, I stopped noticing it on my head. It was just there.
Made a day trip to USA kilts to get properly sized which I think was a key factor in it being properly sized.
I suspect it may see more use than I was expecting. I like hats and it serves quite well in that regard.