I can offer suggestions on experience with some of the current production tubes, but since I do not own a triple or dual rectifier amp, perhaps someone else could extend some suggestions that work will with your amp.
I would definitely consider a Long Plate Sovtek 12ax7 for the PI. I have found that to be the best in a different Mesa amp. Best to get the snake oil with it (matched triodes). Matched triodes will have equal drive capability for class a/b power sections. It will not reduce or alter crossover distortion which is an inherent characteristic of class A/B amplification.
Tung Sol performs well as a primary tube (v1). I have began to like this tube and has made its way in both my Mesa amps.
EH is a good tube that can be used in any location. Has good saturation characteristics, not as deep as the Tung Sol. The case with my Mark IV ( I have EH in V1, and Tung Sol in all other locations. I am surprised how good it sounds.) Consider than as an exception.
For high gain, I found the Ruby to be a better choice than the JJ equivalent. It was not as fizzy as the JJ or mesa 12ax7a tubes. Ruby, JJ and Mesa 12ax7 are essentially the same tube. I actually prefer the EH tubes more than the JJ. The tubes that I had ordered from Doug's tubes were all tested and marked with their respective gain per triode. The EH tubes had higher gain ratings than the JJ HG and Ruby HG.
Avoid Penta Labs LP tubes. Overall they are not all that bad, but have high tendency to go microphonic in a high gain amp and it did not matter if the tube was in a current driver location or gain stage. Seemed to have scooped mids in tone when used in gain stage. Current driver would be reverb or effects loop return, as well as the PI.
