Holacracy Community of Practice Archive, 2015-2019 Community Holacracy Web Site
Hi Florian,

I'm in touch with an agile coach in Hamburg. His name is Alexander Krieg. He published an maturity framework which allows assessing your topic (excluding Holacracy). It is currently available in German.

https://fg-wi-vm.gi.de/uploads...Alexander.Kri....pdf

I'm sure, if you get in contact with Alexander, he can provide you with additional information. His contact details are mentioned on the last page of the pdf-file.

Hope this to be a helpful hint.
Good luck for your project. Writing a book is very hard work!
Cheers
Andreas