AllThumbs....I've looked at that needle setting chart on the OS web site (not owning an OS) and it's very confusing. It's not actually based on the needle being fully closed (because then your engine won't run at all) but it's based on whatever needle opening you need for proper operation. For instance, the maximum lean (or peak) setting at the 3 o'clock position could mean that the needle was open 1 1/2 or 2 turns from fully closed. All the other positions are just a general guide as to where the needle should be to get a certain mixture. BTW, they're also assuming you'll put a file mark on the needle end so you can see how far you turn it. What I do is close the needle (gently) then mark it at the top or 12 o'clock position. Then you can see exactly when you've opened it 1 turn, 2 turns and so on.

The number of turns the needle is opened is going to vary depending on what type of fuel you use (mainly) and most engines need about 2 turns or more to be certain they won't run lean, especially on the critical first start of a new engine where you have no idea how it's going to run. The only setting that's instantly recogniseable is where the sound changes from a 4 stroke (deep growl) to a 2 stroke (higher pitched clean sound). That's the equivalent of what they call the 9 o'clock position but the needle itself could be open maybe 2 1/2 turns from fully closed.

The OS diagram simply means that full lean will be about another half turn closed from that point (once again, more or less depending on your fuel).