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Ken --
I'm not sure just where to start but I guess I'll have to ask you to forget, temporarily, all test methods you've learned from zone system references. You will have trouble arriving at a useful conclusion if you try to mix the two procedures.
If your meter won't read EV 2, set up the enlarger to provide EV 4.0 (suitable for ISO 100 speed films) then stop down 2 stops. Real precision isn't important at this early stage because the BTZS test methods discover the "ISO" reference by "locating" in the curve family a curve whose average gradient is about 0.62 (which satisfies the ISO/ANSI standard for film speed determination). If you're calibrating the curve family by hand, draw a line through the curve toes connecting the points that represent 0.1 over base plus fog; this line will be slanted a little because the B+F densities will increase a little as development increases.
Then use the little "ISO triangle" described in the book to find the speed point of the 0.62 curve on that line, and mark the exposure value on the x-axis as the ISO reference point. Having found that point, use it to calibrate the other curves' speed points; each third of a stop represents one film speed value, and points to the right on the reference represent speed loss. For example, if your "ISO 400" reference falls on x-axis density 2.3, and another curve's speed point falls on 2.1, that curve's speed is 2/3 stop less that 400, or 250.
This is a very simplistic summary of the test procedure (you won't know from this version whether your film's ISO is really 400 or not but you will find valid speed point _locations_). A further test can establish the actual speed value, after which we would normally switch from the 0.1-over-B+F speed points to Contrast Index speed points.
I would strongly suggest that you download the free demo Plotter program and use it for your tests; it makes all of these calculations for you and speeds everything up tremendously.
If you're seriously interested in working with BTZS methods, please read the book carefully and try to follow the reasoning, if not the actual procedures. When you have a handle on that, let me know and I'll try to answer your questions. But I encourage you to try the Plotter demo; it's a very helpful program and working with it will help you understand what BTZS is all about.
Anybody else want to chime in here?
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