Re: Nickel Silver vs. Brass
even Fender has done significant research at least on the Telecaster baseplate. But could be outmof the ballpark again because guess this is humbucker issue.
The Tele base plate is a different situation, because for one thing, it's somewhat closer to the coils than a PAF base plate, being attached directly to the bobbin, and for another, a variety of metals with varying degrees of thickness have been used on Tele bridges, including some permeable metals, such as steel, whereas the metals in question, brass and nickel silver only really vary in terms of conductivity, and are both non-magnetic.
Even then, Telecaster base plates make only a very small difference. They were never put their for tonal reasons, though the historical revisionists like to talk about how they increase the inductance, and make them sound fatter, ask someone precisely how much a base plate of a given material increase the inductance by, and you'll hear crickets. In other words, everyone just takes everyone else's word for it.
The reason they're there, based on what we know of Fender's priorities at the time, is either to shield the under side of the coil, as the top side was supposed to be covered by the "ash tray", or to provide threading for the three large mounting screws. Subsequent pickups designed by Fender had no base plate, and used smaller screws with wider threadings that would hold securely to the fiber bobbin material, so Fender apparently felt that whatever benefit the base plate provided wasn't enough to justify keeping it around.