Tubes for Cary SLA70 Signature

I have to retube my Cary SLA70 Signature and I need your suggest and recomendations.
6550, KT88 or KT90 ?
I contact some tubes distributors and they gave me many recomendations:
Tesla KT88
Tungsol 6550
Electro Harmonix KT88 and KT90
Svetlana or SED KT88
Plese let me know your experience and suggest.
I suppose the first question to ask is whether you were satisfied w/the tubes you are replacing. The second issue is tonal balance, as each brand supposedly has a different one. In researching tubes on Audioasylum and other sites denizened by tube heads, I've concluded that the biggest determinant of how a given tube sounds is the circuit (and bias level) in which it is used. Finally, are you sure that this amp is limited to these types, as some amps that accept these can also accept EL34s, supposedly a warmer, yet slightly less powerful tube.
I have an SLA 70b Signature driving a pair of Legacy Classics. My favorite combo so far is SED KT88, Mullard GZ37, and RCA red base 6SL7. Beautiful mid range and solid bass. The highs are extended, very pleasing. Just remember, 'Tube Rolling' is half the fun. Thanks, Patrick
KT 90's not the EH, go to upscale audio and get some tested and warrantied Ei's.