Great guide 
Sorry for replying to a very old post, know you shouldn't really "bump" old post but since it's a sticky I thought it's fine! Just a question on this step:

Sorry for replying to a very old post, know you shouldn't really "bump" old post but since it's a sticky I thought it's fine! Just a question on this step:
How long should you use each sheet after 220? Like the 220 grit ish is to get down to the copper, when you're there and move onto the 400,600,800,1000 and so forth, how long should you use each of those sheets for before moving on to the next grit?5. Once you reach the copper (and sharpie'd X is gone) on the CPU take off the 220 grit sandpaper and switch it to the 400 grit, tape it down, and start going in circles again. - follow step #4 lapping procedure (rotating object being lapped 90º after every 15-20 seconds of sanding/lapping)