Start with rebound in the fastest setting and the lockout off. Find a good, smooth fast corner you're comfortable attacking repeatedly. Keep adding more rebound damping until the bike feels nicely settled mid corner and through the corner exit. If you've got too little rebound damping the bike will want to push wide on exit, if you have too much then the bike will feel like it wants to "knife-in". If in doubt, too fast rebound damping is always better than too slow.
How many clicks of rebound someone else is using will not be applicable to someone else, so pretty much ignore anyone who suggest a certain number of clicks as a great rebound setup. The SID rebound adjuster is not accurate from fork to fork and how much rebound damping you need is entirely dependent on how you ride (how much weight on the bars, how you smoothly you transfer that weight on braking, how hard or smooth you apply the brakes, how smoothly you stop applying the brakes, how much you use your arms to absorb bumps etc.).
If you change your pos air pressure then you may need to re-adjust your rebound to suit (typically more damping with higher pos air pressure).