I AM LOOKING TO BUY A SMALLER COIL FOR MY F75 AND WANTED TO KNOW WHICH WOULD BE BETTER FOR HUNTING TRASHY CIVIL WAR CAMPSITES. THE 5 INCH DD OR THE 3 X 6 INCH ELLIPTICAL COIL. THE PLACES I'M HUNTING ARE CHALK FULL OF SQUARE NAILS AND I HAVE FOUND SOME NICE STUFF WITH THE 11 INCH DD COIL BUT THINK I MIGHT DO BETTER WITH ONE OF THE 2 SMALLER ONES. ANYBODY HAVE IN SUGGESTIONS I WOULD APPRECIATE THE INFO. THANKS