How do you define typography styles in your designs?

When defining a style guide, which of the following is most common when naming layout components?

1. Stating the specific H-levels to be used (i.e. H1, H2, etc.)
2. Create your own set of naming conventions (e.g. "Top-level title", "Subtitle", "Body text")?

If you use the first option, it seems you'd run into cases where those rules don't fit. For example, on one page H1 is good, but on another page, it needs to be modified to fit well in the page.

Essentially, how specific should a style guide be?