So here's a very quick and dirty sketch of how to feather copy lights. Lights should be in the neighborhood of 45 degrees from the copywork center, but far enough to the side not to give specular reflections off the flat art. Aim the strong center of each light beam at the opposite edge of the flat art, which uses the inverse square law to get you even lighting across the subject. I don't know why so many examples show both lights beamed right at the center of the work, but feathering usually gives much better results. And be sure to keep direct light off your lens with a "gobo" or flag (card for blocking light) if you need it.