Ausable,
The pinch test will tell you if you are in the ball park.
If it idles decently well right now turn the low speed "in" slowly and for every 2 hours of adjustment just blip the throttle (on a starter box or something that will hold the trucks wheels off the ground) once it goes to a higher idle and stays, back off on the low needle 2-3 hours, blip it again to make sure the idle comes back down to how it sounded before it went up. If the idle goes up after the blip but comes back down within 2-3 seconds you are real close. This will get you close and let you run it to get the high speed set.
Then go to the low speed. Just remeber that the high speed affects the low but not the other way around.