My Papa Doble Cocktail

This is a great cocktail -- very well balanced all around.  I'll spare you all the Hemingway trivia cluttering up other recipes out there. The original recipe I found called for gold rum, but having none on hand I substituted a mix of dark and light rums. I am pleased with the results. Make one of these on Papa's birthday, July 21. Mark you calendar.
Warning: This makes a very large single drink. Consider sharing it with a friend.
Musical Accompaniment: Chan Chan by Buena Vista Social Club