Tube Selection Help

I have had my tube gear for at least 10 years, but never though much about the actual tubes in the gear. I currently have a VTL TL2.5 pre, pair of re-issue VTL TT-25 amps, S3/5 Spendor speakers and original Rega Planet CD player. I listen mostly to jazz, folk, bluegrass, acoustic type music and like a warmer side of neutral sound with good soundstaging. Current tubes are: (i) pre - 2 X 12AUTA, Sylvania yellow bolt USA label and 2 X 6350 no names I can see - black plate and D getter and (ii) amp - 8x EL 84 current issue by JJ and 4 X 12AT7 JAN Philips (I think made on 10/85). If it matters, I have a picture of the no-name 6350 and the Sylvania and box markings for the Philips. I would appreciate any thoughs on these tubes in my system and what tubes to consider replacing first to improve the sound that I like. Thanks