In any case, for those who experiment with room treatment and other tweaks like vibration isolation, etc., you need to re-visit the speaker set up track *every time* to add or change room treatments or tweaks. Otherwise, things can easily get out of control. Complexity is not your friend. In fact, the best course of action - remove all room treatments from the room, and using the out-of-phase track as a guide, slowly introduce the room treatments back into the system, moving the speakers as required to get the best results from the out-of-phase track. Then, placement of diffusers, absorbers, Helmholtz resonators, tiny bowl resonators, crystals, what have you, is a snap.
It also helps to have a SPL lever meter and test frequency track on hand to be able to map out the 3 dimensional space of the room to get a handle on where room treatments should be placed initially. For example, Tube Traps are sometimes best when placed a foot or two *away* from the room corner. It depends on where the standing wave sets up in a given room. There’s also the empty box trick for locating standing waves and similar sound pressure peaks in the room that can be employed.