You're welcome. Another thought... risking stating the obvious. If cleaning the regulator points doesn't help, make sure the connections are all clean and tight - generator, regulator, ammeter, and ammeter to starter solenoid, battery cable and grounds. Possibly some recent corrosion or a vibration loosened connection, I suppose, since the meter used to be steady. Not sure exactly which regulator you have, since 12V converted, but the attached Delco bulletin copy dated 8-1-60 has the procedures for cleaning and adjusting the points in case you need the info.
I suppose there is some irony in all this - I should probably see why my ammeter is bouncing at low charging current, too. I assumed it was "normal operation."
