BIG CHEVY 3600,
Yes, the gauge of set of jumper cables will determine if they might be useful when starting a 6v vehicle. Heavy duty jumper cables cost more because of the much heavier gauge wires (and clamps).
Yes, your observations directly relate to this discussion. Denny's study relates to jumper cables, too - size matters, up to a point (some us would say that 2/0 is that point and no one seems to be arguing in favor of a larger gauge).
Tim
