Chinchilla? What kind of hat are you making? How many are you casting on? Does it have ribbing?
I always use a soft acrylic or acrylic blend for chemo caps. The last several I made I used Berroco Comfort. I usually use a ribbed edge although one of them had a garter edge.
You can see them here.
ETA: Oh I see... I looked up Chinchilla and see it's that fuzzy stuff. I prefer my stitches to show so I've never used it.