I think the groups of four is a better method, especially if you factor in the chance of a runt growing on either side of the barrier.
In the pictures, I see one powerhead. Make sure you can provide adequate flow to the other side since you've got it screened. When I did a test for growth of macro algae years ago, I used identical powerheads in a divided tank to maintain equal flow & oxygenation.
In the pictures, I see one powerhead. Make sure you can provide adequate flow to the other side since you've got it screened. When I did a test for growth of macro algae years ago, I used identical powerheads in a divided tank to maintain equal flow & oxygenation.