I have used both coils on the Elite, GT, and the Excal.
I can't tell depth differences, but I can tell you the area coverage is a big plus on the WOT. If you hunt slow enough, you can use the WOT in a trash littered park and still pick out the good stuff.
Weight could be an issue if you hunt all day. The S-12 kicks butt. It's not as big as the WOT, and the weight of the S-12 is very light for its size.
The stock 10-inch Tornado is very good as well.
The compromise between the stock coil and the WOT is the S-12. The S-12 can be used as a general coil. Just sweep slower and listen carefully.
As for the sensitivety settings, I have found that the larger the coil, the sensitiviety setting needs to be set a tad bit lower. This, I believe to be true in more minrealized areas like the salt beach, wet sand. Another factor will be outside interference like power lines. In an wide open area with non-mineralized soil, and no power lines, you prolly could leave the machine in MAX setting with little or no falsing.
laterz
ed