I definitely think that the lack of black coloring is because of the bubble-tip. I have to get around to getting a carpet anemone, I've just been lazy. there is an LFS by me that have them.
with the matter of size, when I got them they were about 3/4-1 in. roughly, they are probably 1.5 in. now. but there gerth has grown nicely. they attack food and are very active.
When I finally get the carpet, I will take a picture when they take to it and then post pictures of the color progress. the black is definitely coming in on them, but looks inhibited, like a orangish grey color, so hopefully the carpet anemone will inspire them to grow some darker colors.
Besides that they are great fish and I won't be terribly dissappointed if they don't go full onyx. I'm not worried about them, at least they are aquacultured and not wild caught.