I have all kinds of places to hunt in town lots, old homesteads and working ranches. All are at least 110 to 120 yrs. old. But the stock coil drives me nuts with the iron. I was looking at the 8 in. or the 5 in. How big is a joey coil and will it work on the Quattro? Any thoughts please? Or is there any other size coil that will work?