I'm joining Steve in giving ACD just a bit of the vapors, or maybe not.
No argument here about the Kna magic in all things Wagner; I have a few of his recordings and there are no better conductors of the canon. He has some equals in particular recordings and performances, but a Kna performance is always special in its blend of detail, mass, and sweep. He's capable of making miserably-sung performances, like that live Tristan, come together and work as convincing music-drama despite the quality of the singing.
My argument is with "the rich, seemingly effortless baritonal heldentenor of [Hans] Hopf." I've got a Hopf performance that is roughly contemporaneous with the Meistersinger ACD has in hand, a Tristan from La Scala that I bought for de Sabata's conducting (surprisingly bad!) and Grob-Prandl's Isolde (stunning, bringing together the femininity and tonal beauty of Flagstad with the high notes, volume, and dramatic involvement of Nilsson). Hopf is an embarrassment after Act I, where he's acceptable. Act II...shudder. I'm afraid to put on Act III. Maybe Tristan is just too much for him, maybe he's lots better in that Meistersinger, but it's awfully hard to imagine Hopf's singing as "effortless."