Seeking best sounding El-34 tubes for my power amplifier

That certainly is a rare bird, I’m sure they are quite impressive. My experience with EL-34’s in other amps brought me to love the Svetlana Winged C’s, but they are pretty much gone. The other issue is what’s still available has been picked over and are new factory seconds , so expensive and unreliable. My Rogue M-180’s make 180 watts each with four power tubes. What I did with them was use new production Gold Lion KT-77’s over EL-34’s.  For me I had that desired mid range and a sturdy tube that endured being run fairly hard. In my case it’s manually biased which gave me more latitude. Although not a direct answer , but possibly helpful. Regards, Mike B. 

I really like the Electro Harmonix 6CA7's that I ran in a couple of amps.

+1 Gold Lion KT77

I upgraded my PrimaLuna’s EL34 recently and went with Mallard’s because of their liquid midrange... definitely worth it over the JJ. I did a lot of research before buying. I think these are the sweet spot. PrimaLuna EL34’s are good as well. 

I'd drop the question in an AI with your equipment and use that as an additional source. You can check it with our recommendations and observations. 

"Best" is always subjective.  List 17 different EL34s, and each one will be someone's favorite.