Another question about 777c2!!!

I fish mainly in 25 fow or less..I am mainly looking for GPS marked brushpiles...

Would it help to have the "Upper Range" set on 5' or more and the "Lower Range" on 25' to get more picture clarity..? I am really not concerned about the first 5 or 6 fow..

Also, I have FishID off..Should I also have the FishID sensitivity to the lowest setting or does it matter since FishID is off?

I also would like some clarification on how "Zoom View" would or would not help.

Thanks for your time..