I am using carbon fiber / nitril buna gasket sheet rated at 800f and with a thermal transfer rate of 60% at 1/16" thickness and a even lower transmission at 1/8" and capable of 400psi containment. This sheet starts at $12./sq foot for 1/32" if and modellers want to try it I sell it for racing motorcycles at britgaskets.ca It is very hard to cut with scissors over 1/32 so I only offer that but 1/16" and 1/8" is available though dangerous to hand cut. The low percentage of nbr rubber allows for stacking of multiple 1/32 gaskets to achieve better insulation and lower heat conduction. Steve Dales founder britgaskets.ca & co-founder of Digiboy multimedia lab '91 Britgaskets Nexus6.1 stirling backwoods motor.