Handyman
In terms of distances I have set up my MAXX very similar to what you have done. However, its very important to be very methodical about set up; I found that changes of only 1/2 inch truly made a difference with these speakers. While it sounds like you have them properly soundstaging, to make them disappear you definitely will need to toe them in more so you just see the inner side. Then
while maintaining the toe in, start moving them small increments toward and away from each other, and when you think the sound has become slightly more diffuse, then slightly alter the toe in further or less to see if this further causes some disappearance of the speakers. Finally check to see that the speaker distance to your listening position is exactly the same. Once this is completed you still may wish to make very small adjustments within the surrounding rectangular area under the speakers which has gotten smaller and smaller. You will need to mark the floor with tape in order to do this accurately. A laser ruler can be very helpful for accuracy so that speaker distances to the listening position are exactly the same.
Furthermore, you probably need further diffusion behind the speakers, not just absorption. I have had success using a 16 inch ASC tube trap directly behind each speaker with the diffusion side of the tube trap facing the listening position. From what you describe you may actually have too much damping directly behind the MAXX. Try removing some and see if this also helps. While these speakers are large, they definitely can be made to disappear. By the way, this can take a bit of time making these incremental changes and listening after each change so don't get frustrated, rather enjoy the journey.
