By the way in Post #19, based on the reflection from the mirror, I do see a way that one of the Tripods/Speaker could have been separated. That chair could have been moved and everything on the left of it could have been shifted over to occupy that space and therefore you will end up with space farther to your left.
To the left was one chair and then 32ft of buffet tables (four 8ft tables). After that was a small space and the cake tables...and there was a desire by the client not to have any PA gear in the background of the cake tables for pictures. Life is sometimes full of hard choices.
To minimize destructive interference point sources of sound should be either touching or separated by more than two wavelengths (which is 22.6ft at 100Hz). In the case of tops, the "best" arrangement is a vertical array - and those cabinets can be arrayed. Any side-by-side arrangement of tops should be cross-firing to minimize the distance between the centers of the radiating plane....and this is what was done. Since I have experimented with this arrangement (both modeling with MAPP and experiments with those actual cabinets), I was able to place speakers in that manner with confidence.
The effect of the cross-firing arrangement offers several benefits over a "straight" or "splayed outward" arrangement. In particular, the horizontal dispersion is greatly improved as a trade off for lower on-axis SPL (which lessens the "zone of death" in front of the speakers). Overall, cross-firing provides a noticeably more even near-field response, for anyone who is within 50ft of the speakers. In addition, the cross-firing arrangement will also improve the "low end" response below about 150Hz (by keeping the centers of the radiating plane less than 1/4 wavelength apart to minimize the nulls). Depending on where the system is crossed to the subs, that can be very helpful. If you have not previously setup tops like that....try it. I think you will be happy with the results. This will give you another tool in your toolbox.