Perhaps @David_Tschumperle as well? We have other colour enthusiasts on the forum that I am sure would be clambering to chime in.
One little idea from me is that G’MIC interpolates its CLUTs, so, in a way, narrow becomes wide. The main issue in my mind is that most CLUTs are designed from the context of sRGB. I mean how many people design their CLUTs with Adobe RGB in mind?