I have having custom stand/canopy built for my new 180, the canopy, the front 8 inches will flip open for easy access to work on it. My question is will the plants be OK if the lights are 8 inches back from the front?
Unless you really work at it, the light intensity will vary in most tanks from spot to spot. So it is kind of up to you to look it over and decide if you are happy with the plants and where they are. Some in the front might want more while some in the back might want less but I would not make a big decision out of 8 inches one way or the other.
Centered might be better but the light location is not one of my bigger concerns.