This can be done with thin foam as well, just need to be careful about the foam/epoxy capability. I’ve also done the same using a rope core (lay the rope in an open matrix over glass or carbon then lay another layer over the top, and push it down into contact in between. Forms a pretty stiff matrix with a reasonable weight.)
In general, I’ll say carbon isn’t worth the effort over well laid glass unless you have some really extreme needs. They both have the same issues with cutting, but the glass is a lot easier to lay up.
@Adam_Xett , out of curiosity, why no metal?