Because I couldn't leave OPI Fly alone, I also tried layering OPI Sonic Boom over it, since they have similar base colours. Sonic Boom is a very sheer blue polish with green-yellow shimmer in it. I suppose you can get it to be opaque eventually, but I should think that it will take 3+ coats. This polish looks the prettiest in the bottle as you can notice some pink flashes as well. I'm not sure how easy is this polish to find (mine is black label) but I have seen a few newer, white label bottles in my local shop. Since it is an old polish, it takes a while to dry on its own, but i think it is absolutely worth it. I suppose the next thing I should do is try to see how many coats it will take to get opaque.