Best 6350 tubes for Joule or VTL

I have a Joule LA150 MKII preamp (best preamp I have ever heard by the way) and it takes four 6350 tubes. I have found that the Sylvania 6350 Green Label Black plate with D getter is the best sounding for my preamp. It was also recommended to me by Mr. Barber as one of his personal favorites. Sadly, they are becomming hard to find these days.

Naturally what tube is best depends alot on personal preference, all of your components and their tubes, and where you are trying to take the sound.

If anyone has tried some 6350 tubes and liked them, could you descibe how it changed the sound and what sort of sound you were trying to achieve?