About 10-12mm of fork showing through the top of the yoke is the general concencus though I think some have gone as far as 30mm. Support the weight of the bike with a car jack under the engine, undo the pinch bolts then use the jack to lower the bike down the forks and hold it at the required position so you can tighten the pinch bolts back up. Won't take you 10 minutes and should make a noticeable difference to the bikes handling and also mean you'll be able to get your feet a bit further on the floor 
I'm not a big fan of the one-size-fits-all approach to suspension settings, there are so many variables which can influence what are the best settings for a given individual on a given bike. Your best bet is to get a mate to spend half a day with you setting up the sag and then blind tweaking (your mate making changes but not telling you what) the compression and rebound damping on your favourite roads to see if you can feel a difference and if so whether it is positive or negaitive, doesn't take long to find what works best for you and your bike.
I'm not a big fan of the one-size-fits-all approach to suspension settings, there are so many variables which can influence what are the best settings for a given individual on a given bike. Your best bet is to get a mate to spend half a day with you setting up the sag and then blind tweaking (your mate making changes but not telling you what) the compression and rebound damping on your favourite roads to see if you can feel a difference and if so whether it is positive or negaitive, doesn't take long to find what works best for you and your bike.