Great! Thanks for this helpful explanation to both of you!
So in Rokas' solution your adding a poly mod, selecting faces of one level, adding uwmap and continuing that procedure for the other levels.
Yes, changing from XY to UV does indeed make sense, blind me!

Was working a little with canvas panting but found that theres no need as its possible to paint scatter areas. Thought of painting colors for rotation though (like in my other post

)
Good guess, using it on an unwrapped texture.
*edit* just saw your answer to my post- actually the same technique with viewport canvas would apply to using a RGB color map to control rotation and paint it on the fly.
Not as super-easy as I was hoping, would work for eg. selecting green color to make things (people) orient to one direction will work, drawing in other directions would need some gradient between colors and therefor ist not too handy..
Anyways, will dig through that 2012 thread. Thanks.