The look I was going for in this scene is that of a room that has not been opened for 30 years. What you want with the dust accumulating in the edges/corners is exactly what I wanted as well, and if you use vertex-painting then this is easily achievable with my shader. If you look at the floor in my screenshots, you can see that the dust on my floor is lighter in the middle of the floor and heavier in the corners - it is just that I wanted some dust covering the whole floor as well for this particular scene. It is easy to entirely remove the dust from the traffic areas if you wish (look at the screenshot where I removed the dust where the door opens).
For realism, the dust covering your scene should be naturally lighter away from the edges, but you also should think about the prevailing air currents: dust will be extra-light under any open vents/windows/gaps as well as in any high-traffic areas. If you have tried my function in your own scene without being able to achieve this look, one thing to be sure of is that you have added enough vertices to your floor mesh! I had to add extra vertices to my original simple box floor mesh (8 vertices), and ended up putting a vertex about every 15cm in my mesh (they have about 1000 vertices now). With enough vertices and a deft touch with the vertex-painter, you can get very fine control over the distribution.
It shouldn’t be too hard to cut in some real-time footprints as well, but I am not planning on adding this features for some time yet. And yes, when 4.9 drops I will explore the possibility of using the new ambient-occulsion query to do some of the corner distribution automatically.
Good luck with it!