The plexiglass worked well but it kept cracking. All three cracked between the mounting holes and the inside thoat cutout. I used radii in all corners but it still cracked.
The Cool Carb design in multi layered. I assume that that the middle layer is a heat sink. I have stayed away from aluminum in the past due to the heat conductivity, and this is why the CC got my attention. I would love to use a phenolic piece but I have not found one made of phenolic that is the shape of the CC unit which I know works.