No, I never used an ss amp with the "higher" Staxes.
It's about 7 or 8 years since a sold my ss Stax system (can't recall the type)
As I judge it, the 4070 matches well with the 007T2; for my ears, the O2 is somewhat warmer, silkier in sound than the 4070 .
I DO prefer the O2 sound, but the singular reason to have the 4070 as well was the better sound insulation
Also -from hearsay - the tube amps reportedly are "warmer" than the ss amps.
From this I would conculde, that the 4070 would rather enforce this tendency of "more brilliant" (as not to say "sharpness") so for me this combination is optimal.
BTW: I'm an analoge & tube supporter, even though most of my (NAIM) system is ordinary ss
but the singular reason to have the 4070 as well was the better sound insulation - actually I correct my earlier statements, that the ATH L-3000 would isolate MUCH better - it is somewhat better, but not enough to sacrifice the quality of sound. Meaning IMHO the L-3000 has no chance against the 4070 or of course the O2