I should clarify that my working space is rgb and not cmyk. But I often check both the rgb as well as the cmyk values in the Info palette. My assumption is that they are "equivalent".
They are not! I think this idea of using a specific CMYK output color space based on something you're not printing to, to look at numbers is super silly. You can just as easily use the source color space upon which ALL other output color spaces will be based.
The numbers often get me within the ballpark. The ultimate adjustments are based on what I see on the monitor and in prints.
Leading me to wonder what Dan would say about this based on his dismissive attitude about display calibration or so many useful RGB working spaces (ProPhoto for one).
The discussion of using CMYK values for skin tones or other by the numbers operation is on going here:
Then there's the question of how this all falls apart in so many raw converters, where you want to do all the heavy lifting (color and tone corrections globally) that don't support nor should, CMYK.
Of course, in Dan's world, you don't use raw files, JPEGs are better. Yes, he said that.