So how would black help out my splash though? If breeding splash to black you get blues not splash right? I think Blue would be the best option and perhaps I can find someone working on blue that is using good quality blacks to improve their blue line that would have a nice blue as result.
Couple things, and please understand that this is constructive criticism, and in the end just my opinion, for what that's worth.
1. The type on your the Splash birds in your photos is average. Most of the birds in the photo appear to be narrow/pinched, and the cockerel definitely is. Assuming they are all related, then they are all possessing this trait. Additionally, their balance isn't right. You can see in the photos that especially the male stands up too tall. Proper balance in a Cochin male is having the eye level with the top of the cushion. The other thing I noted in a couple of the photos is that the lobes on the females appear to have some white in them. That is not something you want to have in your line if your goal is to have a good string of Splash Cochins for show purposes. White in the lobes is color foreign to the breed.
2. The color on the females is pretty nice. Keep that as your goal and you'll be fine.
3. You could find a Blue to use and as long as you find a top notch Blue, then that would be a good way to go. However, top notch Blacks are easier to come by, and if you went that route I'd locate a pair and breed both Splash male x Black female, and Black male x Splash female for some genetic diversity. Granted this produces no splash in the f1 generation, but you'll have some nice Blues to work with in the f2 and beyond years.
For your consideration. Most of the people that I know that show splash in other breeds, don't specifically raise Splash in that breed. They breed Blues, and then get the splash as a product of the Blue breeding. Splash x Splash will dilute to the point of a washed out white as has been noted by others in their previous responses. Also, your number one priority, if you are breeding with the show hall in mind should be type. Type first, color second. If you don't have Cochin type, then it's just a splash colored chicken.