All of that information is relevant to what spacer you are using.
Your OEM wheel is hub centric, as well as all other wheels specifically for the Nissan 370Z.
Not all spacers are hub centric, and in the case that they aren't you'll have to measure it accordingly. If you have the proper wheel spacer, you shouldn't need a hub centric ring.
Find out what size you need and look at it on here...
Wheel Hub Centric Rings - buy wheel hub rings online from 1010tires.com