The original recipe passed to me by Bacardi doesn't state, but I agree with you that white balsamic would be better for both taste and appearance, so I have amended the recipe acordingly.
Really interesting! I came to it through my love for Riesling. So I doubled its part. I used 2cl Riesling and 4cl Bacardi. It's a little bit of with the acidity, but with this name this shouldn't be the problem! A dry and balanced cocktail.