I have to ask. Are you sure you need all that power?
I had monster solid state amps for well over thirty years. It was clear that more power made a big difference in the overall sound quality. Overpowering was always good.
A few years ago I switched to tubes. Audio Research Reference 160m and 160s. They can be run in ultra linear mode with 140 wpc or in triode mode… 70 wpc. My Sonus Faber Amanti Traditional have an efficiency of 90db… 3db less than yours. I have found they sound better in triode mode (a touch more musical). So I run them in triode mode. There is no noticeable difference in volume between the two modes (yes, counterintuitive). I find with tubes the wpc is very little difference in sound unless you are really under powering, unlike solid state.
I listen to them in the 70db - 80db range at most usually. I had some youngsters over here to listen to them. They listened at way more… in the 90s. They sounded great… no loss of dynamics. Although I had to leave the room… I don’t like music that loud anymore. They were listening in triode mode (70wpc).
The new Audio Research Reference amps REF 80, Ref 160, and the new REF 320. Have automatic biasing. Also the tubes are slowly brought up to full power over three and a half minutes to increase tube life and prevent the power surge that can pop tubes and take out resistors. Tube life is three thousand hours… and retubing is only 8 power tubes in total.
Taken together, I would recommend you consider trading your amp for a REF 160s or REF 160m monoblocks. I have had both, the monos have a wider and deeper sound stage… the stereo has a bit greater impact.