If you are going to use a black and white background, it really has to be mostly white. Something that "reads" as white with a little interest on it.
Your X blocks are really dominant looking. I think part of it is that your snowball corners are so big. They are usually the same size squares as you have in your 16 patches. Not that it's wrong that way, just an explanation for why it comes out different.
What I had in mind was the smaller red corners like in your first photo, and then a mostly white background. A white with thin script on it would be awesome with those colors.