Quite a few questions really, but better to know then what to know

I use a RS in my Micro LRP Shark ST, Xfactory X6 and my SC10, they work great but wanted to understand what the hotwire settings REALLY mean
Neutral width - I always read this as a sort of 'dead band' on the throttle so I always set it to 0, a lot of people seem to dial some of this in though so whats the real meaning of neutral width?
Timing advance - People also run this alot, I've always set this option to 0 as I don't quite understand how turning it up would be beneficial? Would be good to know
Other than that top stuff, just need to understand a few terms