Sorry I think I might have been misunderstanding what you're trying to do.
In your main Loader folder there is a file called settings.txt that handles your Loader configuration. When you create custom character folders inside the Mods folder you can put a copy of that file in there to change Loader settings on an individual character basis. I was also suggesting that you delete lines in the file that you do not want changed and only include what you need as to not override unnecessary things when switching characters. The idea being that you could have reset-on-character-change disabled allowing you to have mostly empty custom character folder that just apply mods and settings on top of other actual character setups allowing you to mix and match setups and configurations. You can repeat this method with individual mod's settings files from the settings folder. Place a mod's settings file in these override character folders to get very different behaviors from all your mods on the fly without having to edit and restart the game. Just make character folders with your various favorite settings and mix and match them either before or after loading and setting up a scene.
This may not be what you thought settings.txt or how character folders work. Take a look at the file and you'll see what it controls.
Edit: what you may have been looking for is character codes. You can generate them by pressing "U" ingame to open the Modding tab. Click the generate button and the text box above will have all your scene's data. You can paste this into a file and name it Code.txt and place it inside a character folder and it will load automatically.