I did loads of research, and continue to. I finally decided on (and really like) NOS Russian KY40Y-9 paper in oil. Can't seem to take them out. If I recall correctly, first they were a bit "warm" for my tastes, but after about 50-100 hours they sound very musical to me without drawbacks. And I really like "warmth", but only if it is without detail loss. I am into the sense of players in the room, just a little softened by musicality.
I installed them floated on bluestick to damp vibration and found sound differences depending on distance and coverage of the material on the caps. The best seemed to be about 3/8 inch coverage, and 3/8 high. Got me, but my system/room is very revealing.
Many reviews say Vcaps are the most detailed and revealing, but find them a little coolish, others don't. Frankly I think speakers, other components, cables and room probably have a lot to do with this.
But I also prefer my favorite 7DJ8, 6DJ8 and 6922 over 6N1P which many prefer in there Torri MkIII...soooo.

And cheap enough to try.
From Ebay today ...4X K40Y-9 NEW OLD STOCK 0.1 uf 630V RUSSIAN PAPER IN OIL CAPACITOR PIO .1