Wow Alan!,
Thanks a bunch for them pics (and to Paul for posting them).
I could look at pictures like this for hours.
Oddly enough I know for a fact that there is an RPM meter of the exact type that you posted above in the Electrical Store (read: museum) at Pareora Freezing Works, south of here, I've used it before. [Linked Image]
I may show my ignorance/lack of knowledge here, but why did you go for 2 motors driving the Alternator?.
Oh and BTW Alan, good to see you've got a Fire Extinguisher there, essential equipment in any workshop worthy of the name.