Ok, started some tubes rolling here.
I've a lot more to do, but I discovered some interesting things so far.
1) 2 Ruby's JJs in a stock MP-1 are maybe too much...very gainy while quiet tubes, but too bassy and you loose some 3-D...
2) a Ruby's JJ in V2 with a TAD 7025 or 7025s in V1 is an awesome combination...and the 7025 is still the winner...
3) Ruby's 12AX7AC5 HG+ is another very good tube...maybe not like a TAD 7025, but very good...and it works fine with a TAD 12AX7-C/ECC83 in V2
4) TAD 7025 in V1 with TAD 12AX7-C in V2 works fine! I've to test with the 7025s in V1 yet...
At the moment, the best combination to my ears is a TAD 7025 Highgrade in V1 and a Ruby's 12AX7ACZHG (the JJ) in V2: it works fine with overdrive, distortion and cleans.
3-D sound, smooth, good overall eq, very low noise, tons of gain, well balanced: I love them!
I've to test other combinations, of course...but I think I found my best.
Ok, I will buy a Mullard RI LP for V1 one of these days...