Umm...I'll do my best
I don't know anything about gauge to be honest with you. I don't really know how to determine gauge.
I can tell you that I have a good size head and this hat fits me
(its big on my daughter--she was just my model).
I used a worsted weight wool yarn.
If you were to increase the number of cast-on stitches to the next workable size, it would be 132 stitches, which would probably work though it might be a bit roomy. I guess it depends on how close to the head you like your hat to be. Of course to combat this, you could do 132 stitches on size 7 or even 6 needles to get the right gauge. Similarly, you could do 110 stiches on size 9 needles. I wish I could be of more help with regards to that--it's just not something I know much about.
If I lay the hat flat is measures about 10 inches across the bottom. I am also a very tight knitter.
Is that helpful to you at all? :thinking: