Yeah, Doug's the man.......I get all my tube from him.
SED's have been my fav's for the past couple of years in both 6L6 and EL34's. My boogie 50/50 has SED's in it and it was a BIG improvment over the stock Mesa's!
You may want to have you're amp tech remove the fixed bias circuit and install a bias pot, that way you can warm it up a bit to where it really should be for the best "tone" (IMO)
Rick