As far as splashes are concerned, it's often difficult to find one that just sits nicely between the darks of crashes and the highs of rides.
They are often too bright, too clangy (bell like) or just plain overpowering.
With a splash, that isn't set up as a stack, I look for subtlety. Out of many I tried, this 8" K-Custom splash cymbal really was the part. It's pitch perfect.
It provides a perfect chromatic contrast between my K-Custom 18" Dark Crash, my 16 K Constantinople and 18" K Constantinople crashes.
Not too volatile, nor understated. Just ... perfect darkness.
8" is a good middle ground as well. 6" can often be too high... 10/12" a little too low.
I can't recommend this splash cymbal enough.