Tubes for my Aesthetix Calypso

Now that I know where to go for good quality NOS tubes for my Rhea........I probably will replace the 2 tubes (per side) in my Calypso. The question is for Calypso owners.....there is a 12ax7 and a 6922 per side. In addition to calling Aesthetix to find out what they say, what tube is the "more important" one to replace.
Thank you for your help and advice!

Rick (RWD)
I think the 12ax7 affect the sound quality more than the 6922 for this preamp. In addition to discussing this with Aesthetix, you should also talk to Andy at Vintage Tube Services.
I am looking for the contact number for Aesthetix but cannot locate it. Anyone have it???? Thanks!!!!

Rick (RWD)
I have been using NOS RCA 5751 tube in the 12AX7 spot and prefer it to 12AX7. Also using the NOS Amperex white label 6922. If you are using stock tubes now you should experience a significant improvement. Check out Joe's Tube Lore on audioasylum it is worth a read.