Ken's correct - Dan tested these under load in the TP and they hit the 6SN7 spec right in the middle. I made the AC post, as philistine, based on another TP owner on AC having an issue. A few weeks ago I took a fresh look at the Treasure spec on the Grant website, and compared it against the 6SN7 spec on the Duncan Amps website. The spec looked identical and Dan's confirmed this in situ.
The rationale beyond this is to find an available 6SN7 that is as good as or, hopefully better than, the best of the NOS tubes that are available (such as the Tung Sol Round Plate).
I managed to wrestle them out of Dan's hands, he's impressed with them, and they're currently on their way to me. I'll update the progress on these.