Previously, I've reduced the lime juice (to 20ml) and upped the cassis (to 30ml) in a quest to make this bittersweet 'n' sour aperitivo a touch more approachable...
You definitely need to like Campari for this one. There are lots of different lime varieties; a friend has a tree really nice smooth tasting limes. Bumped up the crème de cassis. 2:1:1. Tastes great to me.