I got back to town Friday, and was back out of town Saturday. But I managed to get some time Sunday to do a bit of work. I've mounted the Carling Contura switches to the switch sub-panel, and I mounted the sub panel below the intstrument panel. The switches are designed to be actuated left-to-right for start-up and shut-down proceedures.
The second pick is a slight modification I picked up from Jon E. next door, a reinforcement tray running forward from the instrument panel. As you can see, I've mounted the switch panel to this, so it can be slightly recessed behind the instrument panel. This should make accidental switch actuation less likely.
Last picture shows the ground buss mounted to the firewall. I spent some time researching and reviewing the Deutsch connectors I'll be using for the wing joins and the firewall, and I'm looking forward to getting some of the wiring done next.