Refined 30-60 watt Tube amp

Atma-Sphere M-60

additionally, ZERO autoformers probably needed for your 6ohm speakers

how about the used VAC Phi 30/30? or one of the ViVa amps?

Yes,
Actually i am very interested in the viva amps but i dont know much about them. Anyone with any experience? Also i am not the biggest fan of the Atmasphere OTLs. I prefer the EL509 tube based OTLs such as the transcendant and custom jobs by guys like george kaye of NYAL fame.

If you're going with 94db+ speakers, I would strongly recommend 300SE type amp.
For SOTA design, you can start by looking at something like Border Patrol SE 300B. You can also have custom amp made from Eletra Print ( who also designed the Welbornelabs DRD amps )

This is one great combo 300B SE + hi efficiency. Some folks think this combo is the music in its purist form.

IMHO, even with a cheap EL84 PP, the sonic signature is already better than most of the high power setup.

Good luck