I mean, as long as you visit libgen with https your ISP shouldn’t be able to tell if you’re uploading books. But yeah, if Tor doesn’t slow down the upload too much, it’s a good protection measure.
For checking on metadata, I recommend you to use Calibre. It allows you to view and remove undesired metadata and you might also use Calibre to automatically add the correct metadata to the PDFs so they are searchable in libgen’s database.