My neightbor has the 6v6 Montille, and that combo with the Aurieges MM is fantastic especially for the money. Great place to start as my Shindo dealer has a
very generous trade-up program.
I recently heard the CV391 Montille, and from what I understand it is a different circuit than the 6V6 despite having similar casework. I will say that those tubes look incredible lit up... so beautiful and when we heard it going into the Latours there was was great detail, clarity, and liveliness, but more notable was the incredible bass. More than I remember hearing with 3-4 other amps at Pitch Perfect over recent months. And those tubes are considered to be pretty much bulletproof.
Can you let us know what type(s) of music you listen to, and how loud? The CV391 is going to have twice the power of the Cortese, and may work best with speakers under 94 dB.