If you interrupt the LRF creation, the temporary files, will be preserved and you can look at them (they'll be in the temp directory in a subdirectory whose name starts with libprs500).
Also libprs500 contains functions that make this task easy. Take a look at
https://libprs500.kovidgoyal.net/bro...ebooks/lrf/web
paying special attention to profiles.py and the individual profile files. As you can see it takes only a few dozen lines of code to create an individual profile.