I have the Stratomaster Enigma and the v6 radio. Not sure how closely it compares to the Discovery Lite.
I intentionally left a bunch of room on the right to add a tablet mount for weather/traffic/etc.
To keep things simple, I also chose not to add a switch (or crowbar, etc) to the charging circuit. I felt like this was a reasonable design for a permanent magnet alternator. My plan if I notice uncomfortably high voltages is to reduce engine RPM and try to use as much electrical power as possible (unfortunately, I don't have landing lights yet). For most scenarios I can imagine, I'd probably have plenty of time to take corrective action if I would have noticed the problem in time to flip a switch.
I spent a while trying to get some information on the voltage regulator we use to determine what the most likely failure mode is, but was unable to find anything.