The pin numbering inversion happened quite a few times back when we started with non-EF91/92/95 driver tubes.
Received now AK5-vector socket extender, C3G-AK5 adapter and a while ago already the Siemens C3GS tubes (thanks superdux).
Just listening to it and it sounds very promising with the HD800s. Larger stage than with the 6HM5 for sure and the first impression is quite nice. Will come back once they are further burnt in. Took a shot from the big tube adapter assemblies put together. Not the most beautiful setup but sounds good as far as I can tell.
For reviews of 6N6P standard compatible driver tubes, look at this
post #3007. It includes impressions from Mordy, Audiofanboy and myself.