I installed the plugin before I found out it does not work for Kindle Touch and went through the whole create collections and restart. Now I know it does not work.
Interestingly when connected to my Mac the books all show up neatly arranged under the documents folder in their own folder names by author then a folder for the book itself. I can also see the collections.json in the system folder. But the Kindle will only show me a flat list. Thanks Amazon!
Meme - I don't believe you do this for money, but if you get this working for the Kindle Touch that's worth $24.99 in software to me so I am not scrolling through 50 pages of books, and I would be happy to make that donation.
Good luck!