Snapping Objects together and separating geometry into different layers

Hey Guys,

I have a problem stacking the objects so there isn't a gap between them. Before randomizing the geometry size it was fine for me to multiply the referenced radius multiply it by 2 and move the geometries.

Now that sizes are randomize this approach doesn't seem to work. Also is there a way to reorganize the geometries into their separate shapes so I can bake them and organize them as squares, cylinders, and circles?

Help would be greatly appreciated!