I have not played with octal small signal tubes.
I have used 6922 (not quite the same as the 6N1P, but similar) in hi-fi stuff over 25 years ago. It would be interesting to hear them. Cascode is what I used back then. Don't know how they would do with bass, but might be interesting with guitar - pentode-like without microphonics
I did pick up some 6cg7s to play with the next round - supposed to be similar to the octal 6SN7, just not as high a voltage rating.
Also, hard to beat the gain of a 12AX7 in simple circuits
They certainly are easy to design with for cleaner applications.
My last preamp had an 3-way-active-Baxandall using 12AX7s and 5965s - too much gain. I am hoping to revisit this in my next attempt - hence the 6cg7s.
Thanks for the interaction.