@ampus,
I can certainly understand the defect concerns; however, that can be stated for any tune, new or NOS. I personally have had no failures with any variants, MKIIs or Art series. My failures were with NOS tubes.
Also, the Octave Jubilee does not drive the preamp tubes hard. There is a high and low switch for gain. The Psvane tubes are in both high and low gain positions. I currently use the low gain setting due to having horns.
I am not advocating or endorsing the Psvane but merely stating the facts as I know them from using the Psvane 12au7 Art and MKiI based on real world experiences.
Since the Horizon is new and not that costly, I am going to order a set to experiment with.