Thanks for your reply Walker! I now understand in potential advantage of creating tonal separations, but for color separation, would you do it the same? Because you want the cyan, yellow, and magenta to all have the capacity to print the entire tonal range linearly, but directed by the CMYK separations however photoshop defines the split, not intentionally manipulating the curve to, say, just print magenta in the highlights or just cyan in the shadows, which I think would be the extent of color control using the method you described?