Because the top of the hat is lace, it is very stretchy and gauge is not crucial, but you may need to adjust the size of the band, which is knit in 2 x 2 ribbing. If you increase or decrease the number of band stitches, start with a multiple of 4 stitches, and then knit one row before starting the lace section to increase/decrease so that you have 72 stitches for the top part.