best 6dj8 tubes for AR sp9mkII???

Hello Gentlemen,
thank you for your kind efforts to educate me.
Digging deeper on the different tube sites, I narowed
the picture and now,aparently, I have to decide in between:
7308 Siemens NOS Gold Pin; 6922 Tungsram ( NOS made in Hungary?);6H23 Sovtek and 6DJ8 Amperex NOS Bugle Boy.
Primary decision input factors:
- the system is very revealing ( Apogee Scintilla speakers )
so as less fizz as possible would be desireble, on one hand;
- there is a cumulated leaness mark in the presence area,
effect of the marriage between the Apogees and Bryston 7b ST's monos( mostly in the low midrange, as I got the combo to ruler flat linearity in between 500HZ-5000kz ), so I'll
go for the tubes which can give a big kick in the low mids.
The overall sound is very clear, and not cold anymore
( due to the c-j Premier 9 DAC with 6gk5 Mullard NOS mark )
but corecting the leaness in the low midrange, would be one further step in chaseing the Audio Nirvana.Any ideeas?
Thanks, one more, to all of you, and appologies for my broken English.

I have never seen a Seimans 7308. Was this made by the American co. Seimans, as this is an American tube designation

Given your speakers, I would say the Ediswan CV2492 is what you're looking for. I've got several pairs running around here. Only wish I had more. SUPER quiet, but not cheap.