Cold brew coffee is an excellent Craft drink agent, especially with Gin & Tonic OR just Tonic Water, that's also a good starting point. Although Cold brew coffee can be used with any type of alcohol (Vodka, Whisky and of course Gin), we even have Coffee liqueur.
Here's a collection of some of the common but exciting craft drinks that we can prepare with Cold brew coffee.
IMO, roughly this should be a good ratio for a G&T Cold Brew Coffee Cocktail / Martiniwithout olives: