Bobby,

I know what you are talking about, long straight wirers make good antenna.  DC produced by an alternator is not really DC, it all has ripples. Some more than others.  Running twisted pairs would eliminate considering the wire the same as the source.  Being able to remotely reset the system at the sources is looking better.  I would guess that filtering out the EMI would throw another fly in the ointment,  more weight, more expense and more to fail.

Bob

"I would think that a plastic plane with the positive cable in an isolated raceway would present itself as a good candidate for the first scenario"

 

 

Bob,

 

You should always run positive and negative wires in pairs and if possible twisted pairs. If twisted is not possible then the wires should lay side by side as much as possible. Isolating a large load cable is asking for EMI.

 

Bobby