Colyn,

 

My only input is to not forget the cabin pressurization. If that in anyway can get into the Valve even when OFF or to the tank vent or tank itself you have a much different problem and fire risk. Some 4P's had engine stoppage when switching tanks with the old stile fuel selector, not the Andair.

 

BTW, what ever happened to those giant under wing Drop tanks that were designed for that airplane that you bought? Did they come with it? As I remember they would have made you the heaviest L4P known?

 

Good Luck,