Somewhat answering my own question, in searching the forum I came across a post by Digger that said:
Regardless, what I have learned over the past couple years of using the CTX 3030 is that, when you implement both Auto Sensitivity and the default "ground compensation" tracking GB, both "functions"constantly monitor the ground for changes in mineralization levels. As mineralization levels change, the Sensitivity is automatically adjusted to allow for maximum depth of detection. And, through electronic filtering, the ground compensation software removes false signals caused by the ground noise. This is what leads me to recommend using Auto Sensitivity (even with an offset) and default "ground compensation, to most who are new to the CTX 3030. We've now reached a point where some of you folks have a good understanding of what makes it tick. For those who understand how these two "functions" compliment each other, I have no problem saying that you may be able to increase your depth of detection by implementing manual Sensitivity. And in some situations, you may increase your depth of detection using manual Ground Balance. However, either can cause false signals and both should be adjusted regularly. Minelab recommends using Ground / Coin separation when implementing manual Ground Balance. However, in the few areas that I felt I had gained performance by implementing manual GB, I found that I could get good results with either Ground / Coin or High Trash separation. Both Ferrous / Coin and Low Trash Separation modes were designed for use in areas with low to moderate mineralization. And once again, low to moderate are too ambiguous of terms to properly identify specific applications."
I am thinking this is the best answer.
Robert
