After I place the last balance light, I start the render and the product is below. Because of the lack of models in the scene it didn't take long for this render to finish. Remember the more you have in your scene, the more time it will take to render it with shadows.
If you have any questions or need clarifications on how to do this, feel free to send me a note on DeviantART. I'll get back to you as soon as I can.
Enjoy and happy rendering.
