When i place the lights, I'm not looking at where they sit on the ground. I'm looking at where the light beam is positioned. So they may not be symmetrical on the ground, but the beams still look most appropriate.
Maybe this pic will explain. See how the lights are not actually across from each other, but kinda offset.
http://i.imgur.com/nfz39zW.jpg
Placing these actually took some time because of when moving the lights the beam goes off. It's very trial n error, but when you get it right you just know it and it's very satisfying to complete a balanced design.
Happy tapping!