I have used 3 coats each of Layla Ocean Rush(blue),Ultra Violet (purple), and Coral Glam with 1 Coat OPI Black Spotted over top.
Yeah, not so much right? I think this is one of those things that sounded great in my head but didn't work out in person. Also, OPI black spotted was so watery it flooded my cuticles and it was so hard to clean up. As is obvious because it looks like I made no attempt to clean here, but I assure you I did. When I went to take it off I found my normal polish remover pads wouldn't remove it and I ended up having to use pure Acetone to get it off.
I do wish the effect was more consistant I may try to play with it a bit more but I'll try to watch for the flooding.