For the electrical penetrations on the firewall I stole somone elses idea. Using some leftover 4130 tube from the control sticks and some 4130 plate I bought, I fabbed up the parts for two tube flanges that will mount to the firewall. The wire is then wrapped with firesleeve and passed through the hole. Another layer of firesleeve goes around the tube and is then clamped to the wires. This provided a fireshield to keep the hot stuff forward of the firewall. The insulation in the firesleeve will eventually break down, but this will buy me time. It is certainly better than a rubber grommet.
I took my fabbed parts to a local welder to stick them together. They did a great job. I trimmed the parts and made sure there were no rough edge to cut wires. I put a coat of high-temp black paint on the steel parts to prevent rust.
I added a layer of high-temp silicone to act as a gasket.
