All the modern 6SN7's sound tizzy and flat compared to the originals. Try any of the WW2 era VT-231's for comparison. Another 6SN7 type you might like, particularly if you find your present line up overly aggressive, is the red based RCA 5692. Your present G.E. at least in my opinion, is one of the least impressive of the original 6SN7.
The Bendix 5992 is a superb 6V6, in many ways perhaps the best of its type ever made. I can however see why some would find it "overly aggressive". The RCA gray glass is the "gold standard" of 6V6's, although ,like the 6SN7 types, any of the U.S. WW2 era production are superb, Just ask any guitarist that's ever played on a Fender Champ. My personal favorite 6v6 is the French Visseaux, which is similar in quality to the RCA but with a touch of Mullard like warmth.
Vacuum rectifier differences will be subtle. The better the power supply design the smaller the influence the rectifier will have on the sound of the amp.
Not saying it doesn't happen, but unless it's defective, I can't see how changing a gas regulator tube effects the sonics at all.
