Can one sync iTunes between two OS X machines? How?
I have a setup in which my entire iTunes library (not just my media folder) is housed on an external hard drive. This allows it to be portable - I take it between computers, open iTunes, and it'll 'update' the database so it can pull from it. All data and settings in mine transfer over. 

The drive makes it easier when managing a very large music library with a multitude of playlists and also want to update your phone from multiple computers/eases replacement of an existing computer. This might be able to achieve the same result you're looking for, and will also address the concerns over space. I was able to pick up a 1TB external USB 3.0 drive for ~$100.