Paul Tomlinson
John, not advice, but a comment on Iain’s choice of Phosphor Bronze. It is often used to construct pickups – it can be formed to hold a shape, but retains it’s springiness, so in this context shouldn’t deform during repeated coupling/uncoupling operations. I haven’t tried to form steel guitar wire, but I anticipate it might resist being formed into sharp angles. That’s not to say, however, that it isn’t worth a try – there’s very little to lose. Good luck.