NOS Tubes for Cary SLP 98

I have read that the Cary products sing a lot better with NOS tubes. If so, which would you recommend for a SLP 98 line stage? Thanks!!
Cary suggested using Phillips 6SN7 nos tubes when I called them with this question; said that's what they're supplying with new equipment now.
Sylvania NOS 6sn7's--chrome domes. Difficult to find.
Early 1950's RCA JAN 6SN7GT's -- expensive.