I have an 8" contact wheel on my KMG and I just winged my first hollow grind a coupe of weeks ago. I just laid it on the wheel until I had a groove to follow.. then it was just a matter of rocking it back and forth to even everything out. What are you grinding with? If I start doing more hollow grinding, I will have to upgrade to a 10" wheel to get more even grinds from edge to spine....