Hey thanks, I will try your tips, getting rid of red first thing sounds good. Covid forced me into studio portraits and being obsessive compulsive about photography I have to master everything with impatience.
Anyway with regard to the OP’s bobsaget question about Sean Tucker’s CMYK formula, I found a way, albeit clumsy. I downloaded a third party CMYK color picker and used the channel mixer to emulate that approach, not elegant but works. BTW , there are different recommended CMY ratios e.g. Skin Tone Correction in Photoshop | Adjusting Skin Color