I position it at the top in the middle. I put it pretty far above the screen, but it has a very adjustable neck and a broad outlay of light, so I have no problems illuminating the entire screen and the sides without glare.
Something for you to consider if you have a Joanns fabrics near you. They frequently have 40% off coupons in the paper for Joanns, and I bought it there. They are sold as a way to effectively illuminate a work surface for sewing machines.