Following a recipe for a "Tequila Negroni" on another site which used Italian Red Bitter liqueur I can say that that is too bitter and swamped the other ingredients. This one sounds more likely to work (ironic because for a while I was using Luxardo Aperitivo instead of their Bitter Liqueur in other recipes!... And enjoying the results to be honest! :-) )

I will like to try this in due course - with some tweaks due to lack of exact ingredients... as a bourbon (and triple sec) version of the Brandy Buck cocktail was very nice and similar to this one.

I also repeated this with bourbon instead of brandy/cognac - a variation on Kentucky Iced Tea without extra sweetness, lazy reuse of the lemon "wedge" too - and it's also nice, the reduced sweetness allowing a little extra citrus to cut through the mix but just as tasty I think. (Too much so, hard to sip and savour either option trying to beat the meltwater!....)

Don't shoot me but I substituted GM with Triple-Sec as it was all I had and thick end of a lemon for a wedge (squeezed so a little extra juice and oils). I also got lazy so stirred over two ice cubes - very nice indeed but the melting cubes dilute things quickly - you live and learn...