Hi!
I just saw your post... Sorry for the long delay in replaying. These are the settings I've been using for a long time. The thing it won't fix is AI aircraft jumping in front of you, or directly behind you, during landing approach. (For that, I started using the "Traffic Zapper" function contained within FSUIPC "Buttons and Key" tab).
Distance of AI to Landing aircraft (NM): 6.00
Distance of User aircraft to AI (NM): 8.00
Heading range for intercept: 40 degrees
Global Approach Fix Distance (NM): 10.00
Minimum Separation Time: 90 sec
User plane Response: Checked (though I question whether it does anything)
I don't show ATC messsages, and don't recall changing the other settings.
Best regards,
Kurt