And if I remember correctly installing the macro and its pre-requisits properly should overwrite values in the profile's prefs.js automatically.
Not really, it has always been the opposite way:
the installation folder defines the default
values, but the user settings in his current profile
folder have priority (most are stored in prefs.js)
Just as a bit basics info for interested people:
Prefs.js in the current profile folder stores only non-default settings of a user (with a few exotic exceptions)
Customized user settings from prefs.js are highlighted in about:config
So, if the user switches a pref back to default, his previous custom settings are now obsolete and deleted again in his prefs.js file. That means, in about:config appears again the default value, without highlighting.
After I edited everything to my liking ... the blank numbers 5-8 were still showing in 'about:config' ... until I finally figured out that I had to reset everything from 'user set' to 'default'.
Yes that's the most frequent and ususally quickest method, for toggling a pref in about:config
Another with the same effect, sometimes quicker to toggle many
prefs at once, would be to close the browser, open the current profile folder prefs.js in a notepad, and delete (=reset) those lines in it, then restart the browser.
Not saying one method were better as the other, just trying to show more possibilities.