Ask HN: Proper etiquette to add maybe-mission-inconsistent changes to Git repo?

I forked a relatively popular repository. Made some changes to suit my own needs locally, which took maybe 60-70 hours. I wouldn't mind submitting a pull request to incorporate those changes to the master. I'm pretty new to github in general though.

And really I'm not sure the changes are "production ready" so wouldn't mind having other interested parties work on it a bit. Additionally I'm not sure the direction of the added features is necessarily the direction the main repo creators want to go, there are no outstanding issues requesting these features, for example, and perhaps even if they would want to implement these features they would want to implement them in a different manner.

The features work but aren't fully baked, ideally I would like to see them part of the master for the personal satisfaction of knowing I added a pretty cool feature set to a popular repository.

So my question is this: What's the proper etiquette here? Should I submit a pull request to the master? Should I submit one to a new branch I create? Should I talk to the owners and see if they're even interested?

Sorry if this is basic!