It`s pretty simple, if you see it. I guess a year of Witcher 3 "modding" gives you some understanding how some stuff works. Still have no clue how to access certain stuff and the lack of CDPR support doesn`t make it any easier. But thanks to a lot of community members stuff like this is now possible.
Also I just added all default values used in the different zones, so you can just freely load Toussaint settings with the click of a button while in novigrad etc.
also you will be able to import / export "settings" by just copy & pasting your settings from / to the user.settings file. I filled everything under a custom category called [KNGRenderSettings]