Timle,
I just realized this is on the digital printing forum and I thought I was on offset. Typically with digital the process is simplified to matching Gracol or Swop with ICC profiles and a substrate purchased just for proving your processes are capable of matching reference values. This is called "G7 Colorspace". Your magenta might not be the correct color but perhaps Swop/Gracol magenta could be simulated using some combination of CMYK on your digital press.
You could certainly aim for "G7 grayscale" and your prints would match Swop/Gracol quite well in neutral colors but your saturated colors, especially reds, greens and blues, might be too "native", thus too dissimilar to what clients are looking for. It's hard to imagine running a digital shop on G7 alone without potentially running into hue complaints in corporate logos, etc., than wouldn't happen otherwise if ICC profiles were part of the process.
Matt Louis