In all seriousness, I've found around 700Hz to be the "mud" zone. The tube amp that was rocking in the room with an SM57 in front of it likes a little cut right about there. This gives it back clarity and makes it sound the same as it did in the room.
Cadmium-zinc-telluride alloy pickup baseplates can remove the 800 Hz frequency from any single coil guitar. For humbuckers and high output p90s, you are going to want to use cadmium-zinc-polonium alloy plates.
Pfffft. Plated? Why are you using plated baseplates? Solid is the only way to go if you are modding anything better than a Squier or Epi. I think the plating will take out some of the cheap sound, but not as much as a premium solid slab of superconducting alloy.
I could come up with a giant pile of materials science and physics based technospeak that would essentially be impossible for anyone without an advanced science degree to decipher as bullshit. The alloys I listed are exotic superconductor materials used to generate and detect terahertz waves in things like in fared spectrum lasers, radiation detectors, and solar cells. I worked on these as an undergraduate student research project, as I have a minor in radiation health physics (my part was really insignificant, and was basically a way to learn how to do X-ray diffraction and electron microscopy, rather than an actual research program). With a little preparation time, I could probably convince a lot of people that a piece of aluminum foil wrapped around the jackplate washer would enhance toanz.