Iridium cut the cable open today and found bad corrosion going about 6" down the length of the cable, and found that some of the wires inside the cable were starting to melt the insulation from the inside out.
He noted that the corrosion was primarily affecting the internal winding of wire down the middle of the cable.
He did test for voltage drop across the remaining cable, however his 12v power source only provides less than 1 amp and there was consequently no evidence of voltage drop. The voltage drop at the amperage pulled to start the car would probably lead to very different results.
We couldn't really even test the issue, either, as the cable deteriorated to the point of no longer working (as noted in the first post) after the smoke-generating cranking that started us down this road.
