Precise number of objects on a surface

Is there an option to distribute a precise number of objects (6 types, ~40 of each) on two perpendicular surfaces (or at least on one of them)?

I need to randomly place all of my objects (tiles) on these surfaces with a fixed grout between them.

Any hints?

There is not a direct way to do that in Skatter, right now.
But you could derive the density from by dividing the number of objects you want by the surface area of the hosts? You can get this information in the “Entity Info” panel in SketchUp.