I think the dual bus, crossfeed setup is excellent. 

 

I reviewed my system with an EE this morning.  This guy is also a pilot and experienced a night IMC total electrical failure in a baron.

He pointed out a couple negatives to the "columbia" style dual bus with cross-feed.

1) if the primary alternator shorts there is no way to run anything on your primary bus because any alternate source will also see the short.

2) if anything on the primary bus shorts in such a way that you can't isolate it with a breaker, your xfeed is similarly useless.

So having an xfeed in some circumstances can lead you to wiping out your backup power source.

 

He suggested isolating the primary load bus so that it doesn't share the fate of the primary alternator.  One way would be with a switch that

can choose either power source (primary or backup) at the primary load bus. Another way to would be to diode feed it (with much bigger diodes)

similarly to how the essential bus is shown on the Columbia.

 

Colyn