I got 2 and 1 each side but one lower than other.
The problem is I have dual overflow boxes in the back corners so I cannot place one more back then the other. Thanks Walt!
Have you thought about adding an MP10 on the back wall? Then you would be able to enable EcoSmart mode. I'm getting 2 MP40s this weekend and plan on putting one of my MP10s on my rear wall to enable it eventually.