Indeed, It is unfortunate that you did not have the time , means or inclination to tube roll the Ref5se. I am confident that substituting an 70's NOS GE 6550A or 60's solid grey plate TungSol would have gone a long way in addressing the points you describe on your blog, whilst expanding upon the plus points you also mention.
"Putting the Aries in, the noise floor was lower. It was quieter. That was the first thing I noticed. Compared to AR, the soundstage was more back and wide, cohesive. The piano tone was fuller and rounded and there was more linearity top to bottom. On an Oscar Peterson jazz piece, both the piano and the double bass stood out clearly on the Aries, while the piano was more forward with the double bass not as clear on the AR"
For me, it was to evaluate how good the Aries Cerat gear is 'out of the box'.
It stood for me on firm ground, certainly if other equipment has to be tweaked to get to even try to get to level to it, it says more about the inherent quality of the Aries Cerat units than anything else. Of course, if I were to be tweaking as well, beyond adjusting the bias to the speakers, then that is a wholly different comparison and game.
Ked swapped his tubes at least 5 times during the session.
Finally, on the famous middle position, as I wrote before virtually all listening was done with Ked in the middle. He offered me effectively once to sit a bit more to the centre, not through a comparison but just one track he particularly liked.
At the very end of the session, I did a comparison, seated from the middle, and it is there that I could conclude already from the first bars the difference between the 45 and the kassandra was not marginal but substantial, though Ked disagreed.
Everyone has different ears and expectations...
Note: Ked actually forgot to mention the triangle on the Oscar Peterson was also distinctly nicer with the Impera (compared to the AR ref5se), showing the improvement was over the full audio spectrum.