I feel like I'm over analyzing this, but since each unit is covering an 18x18" footprint it shouldn't matter whether the unit is parallel or perp with the tank, right? Looking to design a light mount from EZTube and would prefer to have the lights perpendicular with tank (cords would exit the backside) but they're currently parallel and it seems like it would be better as the pucks run with the length of the tank. A little help please