What would be the need for the baffels then? I was hoping to set up a wider bubble trap with an egg crate bottom to use for a media tray in case I wanted to run carbon or gfo bags just before the water enters the return compartment. So the largest section would actually be the intake where the roller mat and if needed the skimmer would be.The return chamber is the only one to be affected by a change in volume. A larger return chamber would facilitate a larger volume of water you could remove without cavitating the pump.
If you make your baffles out of a permeable material, essentially the whole sump will be a return chamber.

