It's my understanding (according to the documents below), the norm is usually one liter duty free but is increased to two liters if at least one liter is manufactured on one of the approved islands, five liters on the usvi. Of course, you can bring back as much as you want as long as you want to declare it and pay duty on the additional purchases. I'd be interested as well if I'm misinterpreting the restrictions.

Caribbean:

https://help.cbp.gov/app/answers/detail/...bbean-duty-free

Alcohol:

https://help.cbp.gov/app/answers/detail/...bbean-duty-free