In general, I am not copying any users.
The result is the same without simple configuration files, with only
1. templates and html folders
2. assignments/sets
Both model courses were copied over from v 2.17 and they were upgraded.
What works at least is that once I import the sets into the newly created course, I can use it as template with set assignments.
Automatically assigning sets to new instructors is a fantastic feature for me, by the way.