There are some more holes to drill on the firewall, mainly for the engine controls : throttle and mixture. I use the Vans dimensions for carbureted engines.
The eyeballs are easy to install but a lot of holes have to be drilled, these is offset by the fact that this model can be installed by one person as the tightening is done from one side only. they were also quite cheap as I bought them during a special sale on some website.




The spherical part has to be drilled to the correct size. The picture shows the eyeball installed on the throttle for a test fitting.




Then I begin closing some gaps on the firewall, using 3M Firebarrier 2000 caulk. The caulk looks much like caulkd for the bathroom but seems a bit more sticky.
I close the hole near the brake fluid reservoir and the one near the gascolator.