I have a spot meter and no in-camera meter. So that's the plan.
Well then, ignore my long-winded post about my methods using averaging meters.
Spot metering and the Zone System were made for each other. Proper film exposure (E.I.) is simply that which gives you the shadow detail you envisage and meter for. There are a few guidelines: Zones I and II are featureless black (maybe a bit of detail in Zone II), Zone III is a "textured" black, Zone IV for luminous shadows, Zone V is middle gray and for shadows in snow scenes, etc.
You base exposure on a shadow value, placing it depending on how you want it rendered. After having decided on your base exposure, you meter other areas of the scene to see where they "fall." Zone V is middle gray, Zone VI is about the value of average Caucasian skin, Zone VII is textured light concrete, Zone VIII is a textured white, Zone IX is pure white at "N," i.e., normal development and print contrast. If a scenes values fall outside the "N" framework, either too flat (e.g., what you want as Zone VIII in the print "falls" in Zone VII or below) or too contrasty (what you want as Zone VIII in the print falls in Zone IX or higher), then you need to adjust contrast somehow for the final print.
In days past, when graded papers were the norm, most ZS users changed development times to make contrast changes. These days, that's not as necessary as before, since the high-quality VC papers we have can take up a lot of the slack. I find I only need to change development times for really extreme scenes; scenes that would be classed as N+2 or more and N-2 or more. In those cases, I develop N+1 or N-1 and deal with the rest of the contrast control with the paper contrast range.
The initial trick is to decide how you want a particular shadow to look in the final print, and base the exposure on that. When in doubt, or if you have no idea, use Zone III for shadow placement. I quickly found, however, that Zone III was too dark for the kind of luminous shadows I wanted in lots of architectural and landscape work, so I learned to place shadows I wanted to render more full-featured in Zone IV. Zone III is good for black clothing, for dark shadows in sunlit scenes that aren't going to be scrutinized, etc.
In any case, I think you can forego much of the testing. Simply rate your film 2/3 stop slower than box speed (which compensates for ZS metering techniques and shadow placement - you're really still using box speed) and go out and make negatives of a scene with a full luminance range where Zone III = textured black and Zone VIII = textured white. Develop one at the recommended time minus 10% and make a your best print on VC paper. If it requires more contrast than a #2.5 or #3 filter, reduce your development another 10% next time. If it needs less contrast, increase development time next time. If the shadows are too featureless for your taste, lower your film speed another notch and vice versa. Just keep good notes about your shadow placement and how you want them to look and the results you actually get. Tweak exposure to get the shadows where you like them and development to get your contrast for normal scenes to hit around #2.5-#3 filtration. That's N.
Use N for everything except scenes with extremely high or low contrast. For those, just start by increasing or decreasing development by 20% for flat and contrasty scenes, respectively. That's roughly N+1 and N-1 development; use your paper contrast settings to deal with the rest.
Best,
Doremus