I think Ralph was exposed to them when i convinced him to install them into the MP-1 Mk3.3 for my client. Which is now up for sale.
They were tested properly here for a good 2 weeks and showed allot of pontial, it sounded better than any other new production 6SN7 i have tried in the past. Exellent and 4 managed to fit into the MP-1 and so far have been excellent and low noise.