The high recovery speed of the Equinox is what really controls its ability to separate targets when the active "center spine" section of the DD coil passes over multiple targets. That is why you get great separation from the the 11" coil. Coil geometry is really a lesser player when it comes to target separation. Even the smaller 6" coil only has a slightly thinner center section compared to the 11" which only slightly affects side-to-side target separation and it obviously has a shorter length. However, the main geometric advantage to the smaller coil is that its footprint simply allows for fewer targets to be present under the coil (including the less sensitive coil edges) at any one time vs. a larger coil. That means the the Equinox is dealing with fewer simultaneous targets which is perceived as greater separation in areas where target density is high. Also, the smaller form factor allows for the ability to physically swing the coil in space constrained areas which allows for target detection in areas where the larger coil cannot be swung (other than in pinpoint mode, target detection requires coil motion). Obviously, too, the 6" coil is lighter. All these advantages are countered by the lower detection depth (2 to 5" less than the 11" depending on the target and local conditions) and the much ground swing coverage afforded by the 6" coil (in open space, I feel like I am tiptoeing when using the 6" coil).
My experience is the coil works great around restricted areas like playground equipment, fence lines, in corn stubble. But does it separate better in thick trash/iron? Perhaps, but really just less targets are sounding off, which is helpful in some circumstances. I really did not get it for separation but for detecting in areas where I can't properly swing the 11" coil. In wide open spaces like fields and beach give me the larger coil regardless of the trash and target density situation unless I want to precisely and slowly cover a postage stamp sized area in that field or beach for some reason.
