So lately Ive been trying to polish my color management/prepress understanding, this time from the printers perspective of ink on paper as opposed to RGB models, monitors or LAB color.

I thought you might find some of this interesting from the 2007 SWOP guidelines.
http://www.swop.org/specification/SWOP2007Specserrata.pdf

It mentions in the report that gray fade-away tones are best if reproduced in all black ink. One thing I know for sure is that desaturation is probably best done in RGB prior to CMYK conversion because RGB can more faithfully reproduce neutral tones (this is one of the benefits of late binding CMYK conversion).

Also of interest to me is the bit on minimum tone reproduction:

“Although developments in digital plating and engraving
technologies have improved tone reproduction
control in the extreme highlights (less than a 5% dot),
designers should still be cautious in placing critical
image components in this tonal range. This is because
all-digital production cannot always guarantee precise
reproduction below a 5% dot, depending on the
process involved.”

As far as TAC (Total Area Coverage) the specification is 300%. This is the total of the cmyk percentages added up in the darkest area of the image. Ive been told that these ink percentages may be tweaked prior to printing and there are other factors like GCR (gray component replacement) that can come into play as well.

There is also a bit about gray balance and CMY percentages: generic
50c, 40m, 40y ratio with a chart that takes into account paper color.

Source: http://www.idealliance.org 2007 SWOP Guidelines

Other links of interest:
http://printplanet.com
http://www.prepressure.com
http://www.creativepro.com