Moscode 401HR tube rolling

I just picked up a used 401HR here on Agon that came with the stock tubes (EH 6CG7 on the inside and Sovtek 6N30pi on the outside). It's not a bad pairing, but I would love to hear from current or former owners on their favorites. I have tried a few 12AU7s on the outside (RCA cleartop was best), but I'm not sure that I prefer them to the stock tubes. Do NOS 6CG7s make a difference? Favorite tubes on the outside?

Thanks,

Ken