Following other's advice, left out the sugar syrup. Made the drink not as sweet. It was wonderful. Perfect replacement for a margarita. Had fresh strawberries which we continued to soak into the cocktail as they were eaten. On my rotation for a margarita style cocktail.
Reading the recipe I was a bit reluctant, but this cocktail proved to be very well balanced and delicious. Using a really very fine mesh sieve improves the mouthfeel.
I used creme de mure instead of black raspberry liqueur (I didn't have any), increased the lime juice to 20 ml and skipped the sugar. Underrated drink. Gonna make it again.