Traditionally made with equal parts gin, Green Chartreuse, maraschino liqueur, and lime juice, but like many others (when using a 40%-43% alc./vol. gin)...
Absolutely an improvement! I tried your tweak with the “French” version, using a 59% Père Labat rhum agricole instead of gin. A revelation! (that might require you’re already into rhum agricole though).