For the record, I agree with everything you are saying, except for that extra wire, especially since OP seems to not want to spend an extra amount on something he doesn't necessarily need. And even though it doesn't make sense on paper, I don't doubt your experience seeing gains with extra runs. And voltage regulators are a good idea.
Doing it that way would require the stock battery and cables be left intact, but you could do that. I wasn't suggesting that there, though that's kinda how I worded it. I more meant that for each alt he needs that much, not specifically from each alt.
---------- Post added at 02:53 PM ---------- Previous post was at 02:52 PM ----------
Lol.