I just started making pot holders this summer. In fact it became 'How I Spent My Summer Vacation.' When I checked on Etsy to see what everyone was using they were mostly made with one layer of Insul-brite and one layer of Warm and Natural. So that's what I did. So far so good. No complaints.
I always have had trouble with large pot holders flopping into whatever I was cooking so I make them smaller...6 3/4"