Thanks for this devonstew, I had not before seen maturity calculated from date of fruit set! I think the number of days is for the hotter US summer, although it matches a little bit this year, for example I reckon (from looking at July photos) that my Kuri’s set fruit around mid July and are now well ripe = 45-50 days. Last year was probably ten days more.
But on the whole I prefer looking at the fruits to assess their ripeness, they are all so fascinatingly different, and many are now becoming visible as the leaves die off..