Help me choose, atom model?

Should I go with clay and design my model of the atom from there, or should I go with styrofoam balls and go from there?

For my element (Copper) there would be a ton of stryofoam balls. Adding up all the Neutrons, Electrons, and Protons, it would add up to 92, and I would just round to 100 balls. For the clay, I can just get a big bucket and design from there instead of worrying. It's basically design or cost. Design being the styrofoam balls and cost being the clay.