300B Tubes

They should handily best your Shuguangs, if my experience is similar. I use Quicksilver SET monos and the difference in those two tubes rendered two different amps entirely. I cannot speak to any comparisons to KR tubes - sorry. I tried Sophia Mesh Plates as well (I don't think they are the carbon plates Philojet mentions - just the standard meshplates) - did not like those at all. In my amps they softened the edges and obscured detail. Two other's I might suggest looking into are the newer Svets, and the Emission Labs. I've used the former, but only heard good things of the latter. The WE's trump the Svets in overal top to bottom balance (they just seem to do everything right), but the Svets seem to be very good at bass and detail while not going too far astray though having somewhat of a harder edge. My amps, my system, my room, my ears, my music. YMMV. Drop the Shuguangs from the list entirely - you'll do no justice to any amp with those...imho. My WE's are early-mid 90's I think - wood box, numbers, etc. Not the new stock you are asking about. Hope you can glean something from that scattered input.

The Sophia Carbon plates sound very good in the Vac ren's....do not use a mesh plate tube. The Vac's require a well made tube and even the Sophia can pop if not up to spec...but out of 16...had to replace a pair...under warranty. These carbon plates are nuetral and have a very liquid midrange...plus the highs are beautifully extended and the bass is full and solid...a great sound especially coupled with the Brimar CV1988....good luck.

FYI: here's a recent post I made regarding my humble experiences with numerous 300B's I own including WE's and the KR's:

http://db.audioasylum.com/cgi/m.mpl?forum=set&n=58904&highlight=coolhand&r=

I should add that from my feedback of users of VAC 300B based amps, the tubes are run pretty hard and perhaps it would be worth looking at the EML300Bxls as this has a higher dissipation rating than the others.