If you are really trying to optimize the exposure then you would need to pick a different filter for each scene (subject matter and lighting) and camera. Shooting in shade (e.g., ~D75) is very different from shooting under tungsten lighting, for example. For color issues, ideally you'd use a separate camera profile for the case when using the color filter, but then again, ideally you'd use a separate camera profile for each lens you use, and other filters (e.g., polarizers). The spectral transmission characteristics of my lenses are similar, but definitely different. In practice, however, nearly all the variation is factored out by white balance. I suggest that shooting with some type of magenta filter is only worth it in specialized, controlled conditions, and even then I doubt you'd see the result in a print. If in doubt, try it.
(To me this is like folks who aren't sure whether to print to an Epson printer with High Speed On vs Off, or 1440 dpi vs 2880 dpi. Some photographers see the difference in the print, others don't. If in doubt, make test prints and evaluate with your own eyes.)