I think Melotheory made an aperiodic rear chamber line array with the TC9FD a while back. I don't know if it is necessary - seems like a well stuffed sealed works very well. If you can make a tapered rear shape to act as an acoustic black hole, that reduces back reflections.
Whipped up a quick baffle. Making the back box now. Not sure about the “wave guide” exit. I may be more scientific about that later. I might wrap the baffle in red leather and paint the back box black.
Nice job You have access to some really nice tools to make speakers with. I've just bought myself a CNC kit to be able to make things that would be difficult without it.
Did you model the effect of the cavity you have introduced in front of the drivers in ABEC? I'm interested because if I was to make another cabinet for my array I would want to try some things out in ABEC before I committed to building.
Those problems will be much worse using a smaller line of drivers if you were to only use one of your 16 driver arrays. 75% floor to ceiling coverage plus is where an array becomes most like the theoretical infinite array.
Awesome finish on the baffle
Some Fibreglass felt and wires and you will be away.