I from the start for my 180 reef tank had the thought to buy the glass cover set for the 180 gal tank for the area for he return wouldn`t allow me to fit around the return pipe. So my thought because of small jumpers like the dwarf eel and jaw fish and so, im best to buy the whole set glass cover and to use only the front part with the plastic strip in order to cover the back of the tank. And with that of course, cover the overflow box as well. For if I was to go with this eggcrate as well, I would have to block the holes at the back of the tank with duct tape, around 3" or so. And that to me would look like a mess, rather then a aquarium to be proud of. But that is my feelings/thoughts on the idea. I guess it all comes down to what we mostly prefer to have and how were willing to accomplish it. And before I forget, which eel species you will have?
Buddy