Good idea. Well, it all depends what you want to test. Normally, such an experiment should try to detect which colours when compared can still be distinguished

Good idea. Well, it all depends what you want to test. Normally, such an experiment should try to detect which colours when compared can still be distinguished, detecting the smallest notable difference/patterns which don't work for subgroups. I don't see how that could work well with the measurement. If it really is about the whole row of colours, then the levenshtein distance could indeed work well.