I'm just re-wiring my panel for a Silent2 Targa self-launcher. I wanted to
simplify the switching and I did not trust the two miniature switches that
were used and which were connected (without any fuse - I will now add one)
to a very powerful engine battery! I have selected a larger high quality
OTTO switch for the master, and I have used latching switches (anti-fumble)
for the Power Flarm brick and for AUX power for a PDA etc. A relay will
automatically connect the solar panel controller when the Flarm is switched
on, so that it will not latch on provided that you switch the Flarm off
before the master. Note that the Vario and radio will be switched off
internally when power is lost. If I see a voltage on the voltmeter then I
will know that the solar panel is still connected to the panel, but of
course it would not stay latched on when the glider is in the trailer.

Schematic here if anyone is interested:
http://ubuntuone.com/162WfU0vGsXXzw2YpKGGif