Gin

4.7 g1 teaspoon

14 g1 tablespoon

Density ≈0.94 g/ml; 4.93 ml teaspoon.

Instead of Gin

Nothing truly replaces gin’s juniper botanicals; vodka is the closest neutral spirit.

Vodka
Use the same weight. It is neutral, so the juniper and botanical notes of gin will be lost.
White wine
Use the same weight and reduce other liquid slightly. It adds acidity and wine flavour rather than gin’s botanicals.
Premium gin
Use the same weight if you have it; it is the same spirit, only better quality.