Once I finalised the yarn choice, I restarted this hat knit from the top down, beginning with a few rows of i-cord. I used the same number of increase points as decreases in the original pattern over the same ratio of rows (ie. increase every X stitches every other row) until I got the required number of stitches equivalent to the original pattern accounting for gauge.

I worked 1 row of handspun to 2 rows of Silk Dream to get as slouchy hat as possible with the yardage of handspun I had.