These are some things that I realized as I was going through the CAD tonight. Taking screenshots and documenting them here for Renzo Villanoy
Make this distance larger (to around 5cm) - there is an end piece on the row of modules not in CAD yet.
Fill in the red area so that it provides more support to the center wall.
The holes for airflow could be lined up with the airflow paths in the modules to reduce the resistance to airflow.