Joe, your next action should be to move away from the computer, get your hands on some transparency film, load up the camera(s) and actually put the meters, side by side, to effective testing, metering each scene identically with each meter, taking the notes (yes, write down what the meter is telling you), exposing as per one meter, then the next, and in the end, scrutinising the results. There must be many thousands of Spotmeter Vs still in use; I have never heard of a spot meter requiring calibration unless it has been exposed to conditions which would give rise to obviously anomalous results (based on experience, not casual theory).

I don't view the battery issue as of much relevance in the absence of testing each meter (and you!) for accuracy. There may be things you need to learn about the use of a spot meter, and these will become evident, especially with slide film (e.g. meter high values (highlights), mid-tones and low values (shadows), averaging then moving up or down based on experience. It's not all that critical or helpful in B&W because of latitude: slide film will brutally convey to you any errors in your metering; it is rarely the meter at fault, but quite often the photographer! Come back and post your observations for the world to see.