
Jamaican-style overproof aged rum is a high-strength cane spirit in the Jamaican tradition, oak-aged and bottled above standard proof.
Two things are working at once here: high-ester Jamaican funk and strength near 57%. A substitute usually brings one of the two, and the question is which one carries the recipe.
Standard-proof aged Jamaican rum
Same distillery character, around 40% instead of 57 and up, and in a drink using the overproof as a small accent, this simply disappears.
Overproof rum from elsewhere
Demerara, Trinidadian and navy blends reach the same strength with far fewer esters. They carry the alcohol and not the Jamaican aroma, so a drink built on funk comes out merely strong.