Truth --
I personally turn the horseshoe button on (disc. off), and leave it on -- all the time (but you have to "turn it on" each time you turn the machine on, as it defaults to "off" each time you power off the machine). I hunt with it "on," (no disc) because in my opinion, it's good to hear the iron. When hunting in the nails, hearing the iron -- and how the high tones behave mixed in with the iron tones -- helps me out in terms of trying to figure out if I'm dealing with just falsing, or perhaps a co-located non-ferrous target with the iron. Like vferrari said, there's no magic bullet, but in my opinion it's a bit easier to learn to try and listen for keepers in the nails when you can HEAR the iron, versus silencing it. It takes time, either way, and of course square nails are much harder to work in than regular, modern nails; square nails sound much better of course (in terms of the amount of high-toning they generate), and as such are harder to work in. It takes time and effort, but in my opinion there is quite a bit of audio nuance available in the Equinox that takes a bit of time to learn. But, over time, you will start to catch on to its language (as evidenced by an improvement in your trash-to-keeper ratio).
Steve