Like Doug said, with the 6" coil I'm looking for separation and target recovery speed not depth. Sure it will go deeper than it's size but the point is to pick good targets out of thick trash. Turning up the sensitivity to max is just going to make iron false louder and shallow aluminum mask more. So I would hunt in Park 2 or Field 2 which are designed for smaller, deeper and harder to hit targets with default recovery speed, sensitivity on 15 to 20 (normal default) and enough iron bias to do what you need to do. If iron is your issue, you can turn down the iron target volume level to very low, change the pitch of the iron tone to one that does not offend your ears, change the iron tone break point and hunt with some iron accepted. I often hunt with -4 or -3 through +40 accepted. If I just press the horseshoe button to accept everything I sometimes get some ground noise on -9, -8 and -7 which is not coming from human produced iron. With the 6" coil, swing a little slower, investigate solid sounding signals from more than one direction with some iron accepted and really listen.