I checked the other thread - there is an example file that does exactly what you are after: using the RGB channels of a texture to control the XYZ orientation of the normals. It is my very last post.
You can use Maya's Artisan texture paint tool - it will live update the painter texture and the normals will react accordingly.
Also, SOuP now has normals styling brush. Take a look:
Screen capture makes it look choppy, but the experience is very smooth, even for dense meshes.