Rogue Cronus Magnum preamp tube

After listening to my Rogue Audio Cronus Magnum for a few weeks I changed the center 12au7 preamp tube from the stock Sylvania to a Telefunken ribbed plate. I got more of the detail I was looking for but a bit too much. Is there a tube that will give me a sound somewhere in between; retaining the warmth and lushness of the Sylvania but adding in a bit more detail?
I'd suggest emailing Mark or Nick at Rogue and asking, they are excellent in responding to questions. Also, if my old man memory is working I think there was a thread sometime back that may actually contain a recommendation that Mark had made, though it may not have been with Sylvanias in the 12au7 positions.
I'm also not keen on the stock preamp tube. Currently I'm trying a JJ (Tesla) 12au7. I've read good reviews on Psvane so may try that as well. I do think I'll check with Rogue first.
Btw, I must say the Cronus Magnum is quite excellent.