There is one other factotre provided by 23andMe that seems to give a subjective feel for the degree of match – that is the ‘percentage of DNA shared’ which may be worth considering as an additional field.
Happy to consider it. I first thought it might be something we could calculate rather than manually enter. But a quick bit of research shows it is a) a complex algorithm based on segment lengths and more, and b) there are multiple algorithms different organizations use. So it would have to be manual, and optional for DNA providers (like AncestryDNA) that don’t supply it.