Did the rewiring this morning, checked the voltage on the cable before and after and it remained constant at just below 10V. Was really much easier than I thought it would be - took me no more than an hour to do 2 batteries and the charger, and only once did I accidently brush the cables together producing a small acidic smell from the rubber shielding, but the battery still seems to have a charge so I think it's ok. I swapped the cables, twisted them together, added some solder, slid some heat shrink over them, shrunk it with a heat gun (borrowed from the old man), and then added some electrical tape on top of the heat shrink to give a little more insulation.
Thanks again Brian and Jason, looking forward to next weekend at Camp Bisco.