I’ve been looking for sources for carbon fibre sheet. I think the arms and legs are 3mm and the back plate is 2mm.
There are some options like this:
and some expensive options:
and some really inexpensive options:
Are carbon sheets graded? How can we determine whether width equates to strength?
One option would be to use less expensive plate for the back and legs, and more expensive 3mm for the arms which get pretty thin up near the tubes.