I followed the steps mentioned at http://dustwell.com/macbook-pro-sharp-edge.html http://dustwell.com/macbook-pro-sharp-edge.html I basically just gauged it by

I followed the steps mentioned at http://dustwell.com/macbook-pro-sharp-edge.html http://dustwell.com/macbook-pro-sharp-edge.html I basically just gauged it by eye. Light, slow, take your time.