Squareback vs round back alternator?

Dana67Dart said
Matt shouldn't the trigger for the relay be ignition 1 (run) as ignition 2 (start) should drop out after the key is let go from a start event?

Yes.

looking closely at the 1960 drawing, Ignition 2 terminal is on the left, Ignition 1 terminal is in the center. Same as later years.