It's a TW, use the seat of your pants.
Turn it all the way in (gently) and back out 2.5 turns if you live at sea level, 2 turns if you live at 5,000 feet. If the bike comes off idle properly with a rapid throttle movement, call it good and forget about it for the next 10 years. If not, there is most likely some other issue than number of turns. I adjusted mine once five years ago and haven't touched it since.