Just a word or two of caution to anyone trying the cones, I use a skew to get them round, but I have also used a roughing gouge, but it is absolutely imperative that it is as sharp as possible, a blunt gouge will cause break out of the "petals". I also only go in one direction with the skew, you don't want the skew to go under a "petal" or you will lose those "petals". I can't remember why I know these things, so no point in asking 
Peter