Do you mean this?
no one knows how to hang the visualization on the overlapping spheres of the actors? (not debugging)
I think you mean visualising the overlap of multiple spheres? If so I would do this by adding a sphere to any actors you wish to visualise. Set the collisions to non and set it’s scale(this method works with any mesh). Next build a material that’s opacity is low and has a color to it. When they overlap they will visually show where the overlap is. You could also use a simple custom stencil mat to show (again in 3d) any overlaps.
Hope that helps