Did a few a while back, best stuff I found was plastic covers off spiral folders, cheap and colourful, easy to cut as well.
Make yourself a see through template first and away you go.
Use a spoon to lever off the needles....carefully!! Also be careful of the thickness of the face you make as if too thick, the needles will jam. Also buy yourself a circle cutter on amazon, only a couple of quid but super useful, a finger drill and craft knife also will help.
Finally a self heal cutting board and clamps is really helpful. Had good fun doing it, enjoy yourself.