I can see where you are coming from with your up and down hone idea, but even if the surfaces begin to look even this could just mean that the edge was hiting the hone uniformally and the bevel is not yet set. I've tried several tests but have settled on the razor across the back of a damp thumbnail. If it bites the bevel is set and as you slide the blade across the nail any spots where the bevel isn't set will slide.I'm still trying to get my head round how to tell if the scratches from the previous hone have been removed as I'm not sure how you tell which scratches have been made by which hone as they all run in the same direction. That's next on my list to concentrate on.