I think the forward windlass battery is a bad idea:
* The savings in weight between heavy wires vs. battery, somewhat lighter wires, breakers, heavy wire between battery and windlass, switches, battery box
... is not as much as you might think ... is just not worth it.
* You must have breakers or fuses
on both ends of the charging wire.
* Weight forward is never a good idea. Wire weight in the bilge
is not so bad.
* Running the engine
or genset really helps get full windlass power. That won't be any help.
* Hard to justify an additional heavy battery that is very rarely used. It will probably be neglected, too.
* You really should have an extra charging regulator
* What if it goes dead? You cannot use the house batteries to raise the anchor
, and the alternator won't be any help.
* When the battery gets weak the breaker or fuses
I had such an arrangement when I bought this boat. My engineer
mind said it was crazy. Tore it out. Now simpler and far better.
You are correct, all that matters is the total cross-section of the conductor, and the lengths be about the same.