I'm with Jonathan on this. Just moving the color filter slider (in ConvertToBW Pro) side to side is a great way to learn what works best for a given photo. As you move the slider, different parts of the image stand out more. I generally go through the entire range several times before picking my favorite for a particular image. I also compare it with the "no filter" setting, and then, as Jonathan says, "refine it with the color EQ and the multigrade settings."
Eric