Rum

4.6 g1 teaspoon

14 g1 tablespoon

Rum density about 0.94 g/ml; 1 tsp = 4.93 ml.

Instead of Rum

Brandy or rum
Use the same weight. Brandy is drier and sharper; add it at the end of cooking so the alcohol flavour stays.
Dark rum
Use the same weight. It is sweeter and more molasses-like, so reduce any added sugar slightly.
Coconut liquor
Use 90% of the weight; it is pungent. Add late and cook 1 minute longer to tame the aroma.