In recent jobs, I have skewed away from pre-mixed rich black formulas in favour of making a black that fits dominant colours in the publication. For example, in a publication with a dominant full magenta colour scheme, I used a pure magenta rich black (C0 M100 Y0 K100) and the results came out great.
In a current job, I have a dominant green that is C50 M0 Y100 K15. To create a fitting rich black for this identity, my first impulse was to add half the cyan and Yellow values to the existing 100% black. That yields C25 M0 Y50 K100. Is that too light?
My question is: how much ink, in percentages, should I add to the 100% to at least have a satisfying rich black? How 'wet' should a good rich black be?
Edit: I understand all that is said in What kind of black should I use when designing for CMYK print? and I'm applying most of it. None of the answers to that question specify how much ink a rich black should have at minimum to be a rich black; to avoid the pale, translucent black of 100K.