Best tubes for sonic frontiers power 2?

IMO most folks who post asking about tubes that 'sound' better are really unhappy with some aspect of the sound of thier unit, i,e, too bright, boomy bass, rolled highs, etc. It would be much more productive if you would post about how you percieve your present sound and how you want to change it.

FWIW, 6550's and KT88's just sound different. Lot of folks like KT88's more but a lot depends on amp design, speaker design, and personal preference, mostly the latter.

IMHO the most rugged and relatively neutral (albeit with a bit of softness in the highs) 6550 is the SED aka Winged C (=C=) made in St Petersberg and in the 90's was sold under the brand Svetlana. Present day Svetlana's are not the same tube. The SED is an excellent tube and is often OEM.

Sovtek's 6922's are rugged and usually very low noise tubes but they are noted for sterility more than anything elso. Very few folks prefer their tone, at least in amps or pre-amps.

Gold Lion re-issues are gaining a good user response - but, unlike many KT88 brands, I'm seeing very few folks comment about 'excessive' mid-range warmth. It seems most user comments have focused on extension and clarity in both frequency extremes.

FWIW.

Thank you,
MY SYSTEM:
MacCormack transport,Belcanto dac3,Rega Apollo.
TUBES: Sonic Frontiers line 2,Sonic Frontiers Power 2.
SOLID STATE: Adcom gfp750,Mark Levinson no.335.
SPEAKERS: B&W N802
CABLES: Straightwire Serenades,Analysis Plus.
Which 6550's should I use? What is better than 6922's?

If your amp will sound 'better' by using 'better' tubes, how in your mind will the 'better sound' sound? Fuller, warmer bass; tighter bass, deeper bass; warmer mid-range, fuller/faster mid-range; warmer upper mid-range, smoother highs; crystal clear and extended highs?

Will the KT88's make my SF power 2 sound warmer and smoother highs compared to 6550c's that I'm using now?
I am thinking about buying 2 quad set of Gold lions re-issues
or Tungsol 6550 re-issues.
thanks