Let me share my journey with the competency framework -
I built my values based on previous work experience and needs.
I just started using the Monitoring of learning plans plugin (very visual), https://moodle.org/plugins/report_lpmonitoring
which opened my eyes that my Scales values have clutter.
In the Site Administration - Open the Scales link. Moodle provides some basic scale. Add/ changes those as needed. If I had to do it all over again, I would not include scale values, such as "Not Yet Completed." Only add in values that are truely unique. Students who do not attempt a course linked to a competency will be see as "-" or Not Rated. That is more that sufficient.
Open up a new Competency framework, explore some of the dropdown list for Scale values. Select a scale, then select the Scale configuration. When a competency is awarded for a completed activity which value is the default and will be Rated as Proficient? Note my Not Yt Completed, values... Once a Scale is in use, you cannot change them. So i live with with unnecessary value.
Cross referenced ID numbers. This is only allowed within the same Competency Framework. I have hundreds of smaller, structures so I cannot use this functionality.
Rules and Rules outcomes you do not need to use. It is over-the-top.
Taxomony is how do you categorize the "thing" the student achieved? Is is a Skill, Knowledge, Competency, ......what do you want to call it?
For a Forklift driver maybe it should be a Skill. For Safety Training it is Knowledge. You can pick whatever term, but it really does not change the functionality.