Premium gin

Measured by weight; no spoon/piece conversion.

Instead of Premium gin

Gin
Use the same volume. Ordinary gin has slightly fewer botanical notes, but in cooking the difference is small.
Vodka
Use the same volume. It is neutral, so add a lightly crushed green cardamom pod to mimic a botanical note if the drink needs it.
Spiced gin
Use about 80% of the volume, as it is more strongly spiced; taste before adding more.