I'd have to agree, Ked. Even though I didn't feel there was a massive step up at The General going from the Magmas to the Mayer 46, that may have been more to do with me really not liking the Pnoes he was using or the music we played that day.
Hearing the Mayer 46 monos at his subsequently on the Gran Sferas horns, and on Bill's bespoke horns, even without a direct comparison to the Magmas, I know implicitly the 46 amps are purer and more transparent likely than anything Nat high power tubes could provide.