The best switch I have seen and I use in my pattern ship is the
"Power Box digi-switch". If it ever fails it will fail in the on position
and the switching is all digital. It cannot be turned on or off by accident
and it has a built in 5.6 volt regulator with heat sink and it is very lightweight.
It has green and red LED's to monitor the battery voltage that can be seen in
bright sunlight and it's not too expensive at around $60.00. A lot of the
European fliers use them including world champion CPLR, Silvestri, etc.

tommy s