Do remember the KR's especially the Black Glass is quite a Tube and will be getting more and more difficult to find a close to Factory Spec' replacement.
Earlier reports made it known the Linlai E 6SN7 was a close match to the KR, hence my interest developed.
It would be nice to know where the Linlai shared a comparative audible quality in relation to the NOS Tubes used in the rolling and comparisons.