This will largely be a matter of preference. Have you considered what corals you are going to have and the space they will consume? This is where I hope the green I am seeing is a type of corraline.
You could consider using the rule of thirds. Place one main focal point one third from the end of the tank, and two thirds up from the tank bottom. Then place a second focal point one third from the other end, but only at one third the tank height.