I'd try some old RCA blackplates (mainly because I have them) and I'd wish I could try some old made in Great Britain Mullards (I'd wish... because I don't have enough of them).
It's hard to say, or know, what the designers of that amp had in mind. They may have tweaked it to sound real good with brand new tubes or it may be a very faithful recreation and seem tweaked for the older tubes.
The impedance and reactance of each tube is slightly different but that stuff is the least well defined in the specs when the industry defines a group of characteristics as "12AX7 tube", or what ever, so there is a range of sound.
The new reissues don't seem to to have anything to do with the items they are named after. You can try any of the new tubes, but you are just shooting from the hip. Don't get hung up on brand names with the new stuff. Feel free to mix and match brands or identify which tube positions have the most effect when you swap out.
You are just going to have to find a combo you like.
Each batch of tubes will have slightly different gain and frequency response... just use your ears while swapping and find a combo that makes you happy to play the amp.
Good luck.
best regards,
mike