One of the challenges is to find new tubes that have the character of the grail vintage tubes. There is a thread elsewhere here on Audiogon about the rectifier the OP wants info on- and various comparisons among users who have tried different new tubes. For that tube, I am using a Mullard first series fat base, which is one of the grail tubes, but even these aren't the kind of crazy money that some tubes fetch. (And I have a stash of other old rectifiers for this slot, all of which sound different in my particular piece of gear).
Ultimately, a lot of people use tubes like tone controls, to flavor the sound to their liking, within a given piece of gear, within the context of a particular system and listening bias. The whole notion of tube rolling is, in some ways, experimentation (subject to using the proper tube that is a correct equivalent). Unfortunately, as TBG said, some of the most desirable old tubes fetch big money.