Thanks Chaley.
From what I can tell, CC acts like a front end GUI for sorting books, then launches an ereader, which in our case would be Moon Pro. I suspect when you close the book it defaults back to the CC GUI.
I watched a Moon+ video where in the screenshot below the guy selects a book, clicks Favorites icon, then creates a new Category name. These categories (Awakes, Watchtower....) that show up at the very bottom of the "All Books" dropdown. This would be PERfect, but we have way to many books to assign manually, one book at a time.
There must be a way to create these "Category" names in Calibre and assign the books. Any ideas?