Once the metallicity, age, extinction and distance modulus for a given cluster have been found, plot the ZAMS corresponding to that metallicity value shifted by that extinction and distance modulus, along with the best-fit isochrone.
Probably this will require to store all ZAMS ahead, when reading the theoretical isochrones. Then each ZAMS can be identified by its metallicity, moved by the given extinction and distance modulus, and finally plotted.
Once the metallicity, age, extinction and distance modulus for a given cluster have been found, plot the ZAMS corresponding to that metallicity value shifted by that extinction and distance modulus, along with the best-fit isochrone.
Probably this will require to store all ZAMS ahead, when reading the theoretical isochrones. Then each ZAMS can be identified by its metallicity, moved by the given extinction and distance modulus, and finally plotted.