If John said he 2N5457 for his build, I can almost guarantee that he used them in ALL positions. If he then said that he swapped them for the originals, and heard no real difference, then I would believe him. He has a LOT of knowledge, skill and experience doing this.
I would read through his comments on this layout, the Catalinbread DLS MkIII.
They might help - there is not a lot of difference between the two circuits really.
http://tagboardeffects.blogspot.co.uk/2013/04/catalinbread-dls-mkiii.html