Joerg makes this cocktail using Bacardi Neo but it also works well with the easier to obtain Bacardi Carta Blanca. If you haven't any Sexy Bitters then...
On a whim I made this with Bacardi Carta Blanca - but having no Sexy Bitters I used The Bitter Truth's Tonic Bitters, lemon zest and 10 ml 2:1 syrup (as per their bitters recipe booklet). Surpassed my expectations- although would knock the 2:1 down to 5ml. The tonic bitters are a winner -there is a hint of green tea following the citrus forward profile.