This hat is extra warm and thick because of the front post stitches all around. For the same reason I suggest using lighter, softer worsted weight yarn, or your hat will be too thick.
For the chain rounds you can use different colors for each chain round, ombre yarn, or just one contrasting color.
I can’t wait to see yours, please feel free to share here, or in my facebook group!
https://www.facebook.com/groups/1619570711639434