I have a 6.6 volt in my M12 - at what voltage should I be charging it?

When I raced back in the day, I was always super paranoid about TX batteries because I broke a gas truck badly when my cheap radio died.

That said - how low is too low?

Should I keep a backup, or do they charge relatively fast since they're such small MAH? (I have the reedy 1300MAH)