Thanks for the inputs  I tend to agree that bigger is better... to a certain limit. I still like to use some some sort of a formula, even if it is only a starting point, to know what my theoretical needs are. I come up with the same numbers as Brak for #6 handling 100 amps, which should already be overkill. By then stepping up to #2 from #6, I would be oversizing by another factor of three. I just don't see how another several steps up to 1/0 or 2/0 would make any further difference. (But I'll be driving through Portland this afternoon and if halekai36 spent $130 on everything I may be sold  that sounds like a great price no matter what the gauge for every cable and lug in the bank and to the starter and back!)
