I have worked and reworked my room using the clsIIz over the years. I would consider doing the following in this order of “easy to do”. The clsIIz speaker will always be very fast, but it can be unbelievably revealing too. The revealing nature of the speaker is what keeps me working it. I stay away from musical systems. You can get the revealing out of the clsIIz, but you can also get PRAT. Getting rid of “lean” is also achievable, but that takes more work.
I follow an assumption, isolate from vibration anything giving out signal, and spike and anchor down any speaker so that you can launch your sound wave. The sound anchors do that well. Just remember that the strut attaching to the oak frame is very important to do patiently and perfectly.
I treat my room and house speakers like a near field setup (only on a large scale) in an effort to get rid of any frequency problems caused by the room or the house.
I use several subwoofers and pressurize the house, once again like a near field setup at the listening spot.
If you can change the crossover for your speakers to 50 or 60 Hz, you might be able to dial in enough subwoofer to blend into that. The speakers will be more lively and the load on your amps will be easier. I could go on and on, but these are the items I would consider first.
If you are lucky, you might have access to:
Someone who has electronic skills, a metcal soldering gun and silver solder? You can modify the speaker electronics.
Access to an electrician? You might want another circuit just for the speakers. Would you consider using better receptacles, power cords, and speaker wiring? Use the electrician or the fellow with the soldering iron.