Fill a 16-ounce glass with ice. Add the light rum, triple sec, orgeat, orange juice, and pineapple juice; then give the drink a quick stir. Splash the 151 and dark rum on top. Do not stir. Make a small cut in the pineapple wedge, then stick a toothpick into the pineapple wedge on the opposite edge. Pierce a maraschino cherry onto the toothpick. Slip the pineapple slice onto the rim of the glass (into the cut that you made). Add a straw and serve.