Although I love the retro Happy Mac, I just can't get past the Gigabyte text that appears in the little black rectangle at the bottom. I may put a black strip at the top and bottom.
In the meantime, I've just been using the white Apple on black background. It looks good with the Gigabyte text, and then when I boot to Windows, the spinning dots look better on the black background.
When I take out the "Show Picker" option in OC, it looks really good with the Apple splash screen that PC has in the OC EFI's. The computer POSTs with the Apple logo, then there is a momentary black out when OC takes over. Overall, it is as seamless of a transition as I can hope.