So I picked up a black w/green splash DV888 - and my kids noticed it turns a cool dark metallic green when it spins. My daughter was looking at the other colors and saw the blue w/red splash - she wants to know if it spins purple? Or does one color overpower the other? Does anyone have this splash?
It really depends.
I’m not really into the splash stuff. Sitting still, it looks bad to my eye with the exception of the CLYW 28 stories colorway. In the retail market, the lack of consistency makes each item unique.
The best way to see one of these splash yoyos is to see them spinning. But, the lack of consistency, well, let me explain it this way. I recently threw a Skyline, and it was I think red, with white splash. One side had more splash than another and it spun pink, which actually looked cool. In general, it had a pinkish hue when spinning but one side was a lot “brighter” than the other.
So, your questions can’t be completely answered. Yes, the spinning colors will affect how it looks spinning. Can one color over-power the other? This is entirely possible, but how it will is unknown until you get it in your hands. I say this because you honestly won’t know what you have until it’s in your hands. Overall though, it should retain more “flavor” of the base color, but a brighter splash color can influence that over to the splash. Since no two splashes are the same, this lack of consistency provides uniqueness, which makes each yoyo a one of a kind. Colorways look best in motion, and I think that’s the best way I can say it.
I do like my xminusmikex modified FHZ in silver pearl base/blue splash. It actually looks like it is glowing electric blue when it spins, sort of high-tech/sci-fi, very cool!
Well it depends, if there is more color than the other it will most likely overpower it. My Jon Rob Supernova is green with purple splash, but there is so much purple that it overpowers the green so when it’s sleeping it looks like a solid purple. This might be the case or it might not. If it isn’t then most likley it will form another color like perhaps purple on the DV888. Hope this helped! 
Well, 28 stories spins mostly silver, but with an almost iridescent purple “glow” that intensifies in brighter light. Since that involves some lighter blue and silver tones along with the red, I’d assume that a strictly blue and red scheme would be purple.
i have the gold/orange with black splash dv888, and when it spins, it becomes a a darker, greyer orange. don’t know if this helps.