Good Tube Selection for Atma Sphere S30?


Looking for recommendations on 6SN7 and power tubes that will compliment the OTL wonder of this amplifier.
erfranke
Some say it is good to mix RCA with Sylvania - that is what I do - seems to sound good. If you do buy NOS, Brent Jessie and Andy at Vintage Tube Services are consider to be among the best at that sort of thing. What does Ralph say? He might be happy with the Chinese tubes. The best new stock I have tried are the Tungsol reissues; Jim McShane sells them and has a good reputation for matching - though I'm not sure that is particularly important with the amps.
I don't mess with the 6AS7's, I use the stock ones that came with the amp. As for 6SN7 tubes I use Raytheon VT-231 in the front row (Ralph mentioned this would be the best spot to try NOS tubes) and Sylvania 6SN7 GTB in the back row. I removed the middle row and use the shorting plugs supplied by Ralph to lower the gain of the amp. Otherwise I just use the stock Chinese tubes in that row.