2 sextets of KT88s or a matched dozen for Defy7 ?

I am just getting ready to retube an amp that has 12 KT88 and wonder if the proper order should be for 2 matched sextets or a matched dozen....

I wish there was a company that rented out tubes so you could audition a few sets to find the right sound for your system.

I am going to try out some Gold Lions and hope they end up sounding as good as my Orchestra Reference system.

Does anyone else have a favorite tube for their Jadis amp?
As far as I remember, my Defy 7 (mk ii) has four bias pots- one for each phase on each channel. If you cannot get matched triads, I would buy four matched quads giving you a spare of each. With so many tubes, NOS is out. I liked the winged C...
You purchase matched tubes in the absence of an individual bias pots. If one bias pot is shared between two tubes, then those two tubes need to be matched. In any event, go to a reputable tube dealer and tell him that you want 12 matched tubes and see what he can do. Most dealers will have matched quads, and all they will need to do is find companion quads if they have a large enough inventory.
Upscale Audio will match as large a set of tubes as you require: (http://www.upscaleaudio.com/rare/tpm.htm) Their screening, burning, and matching procedures are second to none. I've been purchasing my power tubes from Kevin for quite a few years, and have yet to be disappointed. BTW- They stock the Gold Lions that your are seeking:(http://www.upscaleaudio.com/New-Sensor-Gold-Lion-KT88_p_70.html) Happy listening.
4est - You are correct about the 4 bias pots, but I did not realize that each pot controlled the different phases on each channel. Very interesting comment that adds a little more light for me. And I also have heard some very positive comments about the Winged C tubes, especially the cryoed version. I wish there was a way to try them out in my system without buying them right away. That would be really nice.
I have another Jadis with the Gold Lions in it and I LOVE IT.

Thanks to Brf and Rodman also.... all very good information.

So far it sounds like either a matched dozen or 2 matched sextets should do the job.