on my tracker IV i have found that my gold wedding band and a nickel both sound at about 11:00 to 12:00 on the disc setting. that's where i set it and i leave it there. i usually run the sensitivity at about 12:00 to 2:00 range and run it in tone mode. that way you still can pick up the gold and nickels, and the tones will give you little hints as to what might be down there before you start digging.
i am in no way a pro, but those are the settings i found worked best for me. hope that helps.
On mine I set the sensitivity high as it will go without beeping on all metal. Then I put it on disc and wave it over a beer bottle cap while turning up discriminate until it just stops beeping. Then good to go on all switch settings. I only just got mine though but I'm finding lots of good stuff, so it seems to work well.