The zone system is living on the edge. Shooting for shadow details, developing for highlights.
Understanding the expansion and compression of your tones under different light conditions is where the secret lies. It's the difference of shadow to highlights that determine the development. Determine the exposure by your dark shadow with details, that will be somewhat just above total black.
To use the zone system you really don't need a spot meter, but instead be more consience of your metered areas. I originally learned how to do it using a Lunar Pro and eventually got the 5° spot attachment, then invested my first born in a Pentax 1° spotmeter. It just made the job easier, not any better. It takes some practice and alot of testing before you get control of your negatives.
Sugested traditional reading is Minor White's Zone System. It's not easy reading. There is a ton of information on the internet that will make it easier to understand and is better written for beginers. Then get the real bible, Ansel Adams, The Negative.
Here is a site that will help you do all the film tests and explains the zone system quite well...
http://www.zone2tone.co.uk/techpagemenu.htm
Have fun and burn lots of film, that's the only way to learn.
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