As numbing as it might be...

So I flipped my drawing to match the flow direction. And added the eggcrate, which I do have. I believe leftmost wall/baffle helps keep bubbles trapped in it's rightmost compartment because they don't have the flow to carry them under the baffle, whether there is carbon/cottom/bubblebuster material #1 in there. No I believe this is exactly the same as Jaded's but allows the baffles/walls to be shifted right, making the return section larger. Your rightmost wall/baffle/piece of acrylic doesn't do anything that I can see other than take space.

Now is it really true that it flows opposite in Australia?