There is little point in perusing Zone System exposure and methodology if your film is sent to a lab for processing. Although it can be and is done for roll film, it is best and rewarding with sheet film, which was the original intention. For colour film I would forget about dreaming of being a Zonista for that from the start. Master spot metering as a priority. This ZS talk will only detract from the enjoyable experience of photographing with the 67, and at this time I think you have quite a learning curve ahead of you, both with the camera's rudimentary, 5-stop range TTL meter and more particularly, the intricacies of metering with a spot meter (1 degree I assume?).
Though dated and a bit dowdy (to say nothing of lousy print quality),
The Negative is a good read (so is
The Print), and contains a number of valid points of methodology regarding spot and multispot metering. AA didn't have today's multispot meters at his disposal and I reckon he would be impressed by their abilities and, in equal measure, appalled by the prices!
The TTL meter is capable, but simple and easily fooled in contrasty light. My own exposures are much longer than the 1 second afforded, so the meter (plus a Gossen Starlite 5 deg meter) are on my person everywhere I go.
There are some tricky parts. Any filter on the front other than SKY1B (light pink) or KR1.5 (light amber) will require filter factor compensation with the spot meter. A polariser (either linear or circular, doesn't matter with the P67) will require a first-set of referenceexposures at varying settings and lighting conditions and filter factors to establish baseline values of minimum and maximum figures e.g. hazy to bright light with a POL filter will usually (not not universally!) require a FF of +1.5. Flat/overcast/dull light will require
+2.0 to +2.3. Red, yellow, green filters for B&W each have their own FF which must be added-in.
Guy Rhodes published a useful first-stop 'how-to' with spot/multispot metering which is worth a read (he is demonstrating multispot/mean-weighted average metering the use with a variant of the Sekonic L758D, but fundamentals of what to spot and where remain true):
Metering for Large Format Film – by Guy Rhodes | The Photo Brigade
It's good that Eric H has mentioned that the Pentax 6x7 / 67 has no lubricants to dry out. That should put to rest endless silly commentary on the internet about these cameras seizing up because "their danged lubes have dried up!".