Hello everyone. Again thank you for the feedback and ideias. I decided to write this script.
It’s here A script to map two color palletes using delta_e_cie2000 · GitHub
It uses delta_e_cie2000 (see deltaE Color difference - Wikipedia) from the colormath python library. This is a standard criteria to compare colors, since only hue or only grayscale, or even rgb mean are not adequate according to several internet sources.
I’m very happy with the results. See below a mapping of fantasy24 into vinik24 (see lospec site)
Of course it’s not perfect since not all colors have equivalents on either side, but for me it seems great enough.