Newborn size:
Cast on 65 stitches, follow pattern, first and last stitch are knitted together when joining in the round to 64 stitches. Brim: 1” instead of 1.5”. Body: K8, P1 for 4”.
Decrease rounds:
Round 1: k6, k2tog, p1/57
R2: k7, p1
R3: k5, k2tog, p1/50
R4: k6, p1
R5: K4, k2tog, p1/43
R6: k5, p1
R7: k3, k2tog, p1/36
R8: k4, p1
R9: k2, k2tog, p1/29
R10: k3, p1
R11: k1, k2tog, p1/22
R12: k2, p1
R13: k2tog, p1/15
R14: k2tog/8
follow pattern

I don’t think the above worked out perfectly, but it was really easy to figure out once you get going.

Notes:
The stitch definition for the Chroma is awful! Should have known because of the variable thickness of the yarn! It looks pretty nice in the pics though.

Was hoping my changes would fit my 6-month old, but it’s way too small. It looks very close to my newborn hats, so I’m going to call it newborn. I don’t have a newborn anymore to test it on.

I’ll post my changes later. My gauge on size 6 needles was 22 stitches per 4 in for this yarn.