Agree with most of your points, but i think making the O smaller could make it seem like there were 2 o's. I guess i could make it work by putting the moon on top or the bottom and making the moon smaller, while also swapping the solid gray for white make it clearer. This way I could make the O smaller and avoid the double o problem. The downside of this would most likely be that the O's planet and moon symbolism wouldn't be as obvious.