That's a great intuitive color book, Lorchen, Visual Coloring. Much less like a text book than Joen's other books (which are all great, if you ask me).
And Anna, when I think of shading, I think it can mean both, gradual changes in value that do not change color/hue, and gradual changes from one color/hue to another.
And if you're asking me, which you're not, you're asking Alex, but I'll tell you what I think anyway.
All greens (lime, pistachio, sea foam, etc.) can play nicely in one quilt if you shade them together. And all values of the same green can play nicely in the same quilt if you shade them together.