Ok, now for the hard bit to explain. I definitely need to explain this a bit. Here's the side by side woofer portion for the center style.
This chart shows the general woofer to mid XO region.
Now, first off note that there's about a 40 degree listening window there. So that's pretty good. I think that works for most people. Second note that with most center channels, side wall reflections are far away. Also note, you never see a polar like this for a center channel MTM speaker. Because frankly, they're very very very bad, all the time. By comparison, this is really good and part of why I'm presenting the data this way. It's the easiest way to see nulls. Ok there's a few things going for us.
What's bad about it, well, there's some pretty deep nulls around 45 degrees. I've proposed to get them out closer to 60 degrees by moving the woofers closer to the mids. Originally I planned about a 500 or 600hz cross over. In the end there was a lot of overlap in the XO and it was around 750hz. This was done for power handling, bandpass gain, and lower/cheaper XO parts count. So in my plan, I spaced the woofers apart a little more than needed to make constructability easier and hoping to match directivity better. With the finished product, the woofers will be as tight as possible, and then hopefully I can remeasure and see the improvement.