The problem w/ egg crate is that if not cut properly (which is a hassle) it can damage the fishes jaw or cut off scales.
Acrylic is much safer and you can leave a little gap on each end so its just enough for circulation to go through or just add another HoB filter
imo the light coves or diffusers work the best easy to cut do not ristrict water flow and plus they are the best choice if u plan on breeding through the divider