Yes the DR, real ones are better. I have a set of high hour ARC stock tubes (4) you are welcome to try next time i am in Seattle. You might also try tge ARC tube dampers, imo essential on the 6H30 as ARC seem able to wrest magic out of tge combo IMO
Brent Jesse Recording supply is a trusted tub vendor w tracer matching.
best to you on the quest.
Jim