Pretty hard to beat Eurotubes (plus it's close for me). They sound good in a Fender. I wouldn't bother with anything other than 12AX7 in your amp. The best way to make it work harder is to turn it up! Mesa tubes are good but cost more and don't sound any better. Electro-harmonix (sp?) high end 12AX7s sound great in V1 position. I don't like Ruby or Sovtek. NOS stuff is OK, like RCA, etc. Again way overpriced. Mullard 'holy grail' stuff is supposed to sound great, but I don't know personally.
IMHO, the single best thing for a Fender Pro would be a better speaker. I stuck some Mesa C90s in my twin and now it sound GOOD! Keep the stock ones for resale time.
Bye,
Dave