Joe, I hope you don't mind me posting a shot using your tutorial method. This is not the best subject for selective color but does work to a degree. Certainly the "fuzziness" slider offers many choices as does desatuation amount.   I have one question:  In converting to bw or greyscale images, we sometimes go to great lengths to get the bw the best we are able. That does not generally include simple desatuartion.   I have difficulty using the tutorial method with images converted by other means than simple desaturation.   

Perhaps  focus of the eye on selective color image is why simple desaturation works well in selective color.  Perhaps a well done bw conversion with selective color will miss the point of bw in the first place and be destacting from the color draw to the eye. I don't know that answer and suspect it is in each person and particular tastes.  

If my post makes sense, any comment will be appreciated.  I have only two days left to be online..ugh! Then off for a week and 1/2 perhaps while work is done on the home.   The first night off line will be difficult...yes.   Any reply is appreciated.        Tom.