Is that why they're big on x-rays? It cracks me up a little to hear them talk like you can't shoe a horse without x-rays, because I don't know anyone who has ever gotten x-rays for that purpose.
No, you've got everything you need to figure a proper breakover point right there on the sole of the horse's foot. All you need is a sharpie and a straight edge. My guess as to why they're so big on x-rays is that they might use them to see if the horse has any structural problems in the foot that can't be seen from the outside. If they do, you might set the shoe differently.