Most sites I visit are brushy, weedy, sagebrush, etc. The majority of them are ferrous debris infested ghost towns and other old sites that have scattered trash and building rubble.
I have some makes and models that, by design, work well with a Double-D coil, but I've tried just about every coil Tesoro has offered on most models the past 35 years, including the Vaquero. On the larger-size coils, such as the new 8X11 RSD DD coil, the Double-D does 'OK' as a rule, but that's not the case for the standard and smaller-size coils. I use the thin-profile 6" Concentric on every Tesoro in my arsenal, and that includes the Vaquero. I sold my 8X11 DD because ALL I use on the Vaquero is the 6" Concentric. The same goes for my Silver Sabre [size=small]micro[/size]MAX, the 6" Con. is my only coil.
Monte