Matt prefers cotton, so I went with Knitpicks Shine worsted.

For the decreases on the crown, I decreased every row instead of every other because I was running out of yarn. I really needed 3 skeins rather than 2, but I wanted to give it to him today rather than waiting another week. I fudged here and there and used as much yarn as I could and ended up with I think 15 rows for the crown instead of 24. I had zero blue left over. I mean, I cut extra yarn hanging from the floats to have enough to finish.