I had my air/fuel screws set at 3.5 turns out which eliminated the popping. The only difference in out setups is I did not drill any airbox holes. My plugs looked like it was running a little on the rich side, so on the advice of a Yamaha mechanic (daughters boyfriend), I moved them in to 3.25 turns out. That gives me a little popping on decel. I currently have two shims, will pull one (leaving one). I had two shims with the jets on my old, Triumph long-offroads and just left them in place.
I don't believe I've heard of anyones setup requiring more than 4 turns out on the air/fuel screws. I'd recommend you wait and see how others respond before making any other changes.
