Coincident Frankenstein mk.2 amps

Charles,
Hopefully, that's what these sites are all about my friend.  To help each other with honest and valued insight.
I know I get that from you and others, but we should always try to listen for ourselves, if at all possible.

Hello Joe, you've described the wonderful pairing of the Frankenstein and Eufrodites. Do plan to keep both your F.W.J2  and the Pass XA30.8 ?
Charles, 

Charles, I traded in the J2 for the XA-30.8

Best,
Joe

Oh I see,  I imagine both  of them sound quite well with your Hornings. 
Charles, 

Hey folks, I am coming to this game late (better late than never!), but I have recently joined the ranks of you Frankenstein mkII owners.  I am running them with my Omega Super Alnico HO monitors, which are rated at 97 db, playing in a rather large room (25' wide x open in back, x vaulted ceiling that peaks around 12').  At 8wpc, wow, they sure play loud enough, and I like peaks in the low 90 db range!

Anyways, lots of good info contained here.  I am looking for any updates / recommendations on the rectifier tubes that are being used with these amps, with either the EML 300bXLS and Shuguang Black Treasure 300bs, which I have.  I like the RCA black plate 6EM7 over the GE gray plate 6EM7s that came with the amp. I have tried the Mullard GZ37 with the EML, but that seemed like a bit too much, and too edgy for me.  Now using Sylvania black plate 5U4GBs, and the sound is smoother.  

What others work "best" with the EML or BT?