What Makes a Great Negroni?

The right ratio. The right vermouth. And the right gin.

There are two competing theories of the Negroni. The first is that practically any combination of gin, vermouth, and amaro in roughly equal parts will do. The second is that there is one and only one right way to make a Negroni, according to the drinker’s very specific preference, or some idealized theory of the drink. 

I think both are right. 

Which is t…