RE: 4.8 V to 6.0 V
The long lock out has been fixed with the 2.4 JR/DX7 radio gear, now if your battery hits the low mark you only get locked out for a second or so. 6 volt is still something you should give a lot of thought to, a second is a very long time to be out of control. Like Chuck mentioned, most new gear will handle either 4.8 or 6.