I found a set of "new in the box" Snap-On inductive ammeters on Ebay, one for measuring starting system current, and the other for charging systems. No wires to disconnect, just hold the meter next to a wire with the current flowing. The box in the picture looks like it's survived a hurricane or three, but the gauges look brand new. For the princely sum of 30 bucks, I'll take a chance!
Jerry