I ordered a new coil for my XT 505, I bought the minelab 10.5" DD 7.5 coil. What can I expect from this coil, how different is it than the standard 9" concentric it came with . I like the standard coil alto , but most of my buddies use DD coils so i figured it wouldn't be bad to have one. How do you work the coil from the standard one.