The exact values of your 0-15 don't matter to me and they don't matter to you either, because you chose to use my 256c colorscheme to begin with.
Then you're not really covered by the article? A colorscheme is all about... color. A TUI is about the content and function. I think there's room to have user-defined 256 palettes that are used by default, while colorschemes can use true color and be chosen by the user if they desire.