I don't know anything about heli's but is it possible to add a second switch for a semi redundant system? As a plane pilot I have this setup on a couple of my planes where I split the battery with a Y harness soldered to the battery branching out to two switches. If one switch fails I still have the other working.

Before every flight I do a switch test by turning off one, checking controls and then turning off the other, I then turn both back on before flying.

If you added two batteries then you would have even a more redundant system.

As I stated above I am not sure if this is an option as I know nothing about heli's

Randy