Hello,
The Tungsol Reissue is smooth sounding with rich mids, but not as much flesh as the JJs. Good Sound in V1 for old Marshalls. In the HiGain Amps I tested it with, the tubes were not the best. The Tungsols are better suited for Clean or crunch. I almost ever found a combination of JJs and TTs beeing the optimum for HiGain. The most dramatic Sound changes are in the V1 Position, the first preamp-tube. So I would start by testing different brands of 12AX7/ECC83 there and then work my way up. If you are playing with lots of gain, as it seems, you should consider buying V1-selected Tubes, which have less noise and are more feedback-resistent. But don't forget that the Poweramp-Stage also has a tremendous effect on how the whole amp sounds. Optimizing and fiddling with the preamp is worthless if the 6L6GC are down.
Best Regards
Micha