Reddit reviews Apple Pro Training Series: Final Cut Pro X

30 days is plenty of time to become proficient with Final Cut. As others have said, the versions can be very different, so you would really need to train for the specific version you will be using.

Either way, I would recommend going through the official training book for the version you will be learning - most likely FCP7 or the more recent FCPX

The book for FCPX was printed before a number of big updates, so the info may be a little bit outdated. Also, the basic book doesn't go into multicam editing, or green screen, or any advanced technique; you would need to go through the advanced book to learn those aspects.