The difference, by the numbers
Both have simple syrup and Angostura bitters. Only the Brandy Crusta has Cognac, Maraschino liqueur, orange curaçao and lemon juice; only the Lion’s Tail has bourbon, allspice dram and lime juice. In parts, a Brandy Crusta is 3½ brandy, ½ Maraschino, ¼ Curaçao, 1 lemon and ¼ syrup; a Lion’s Tail is 4 whiskey, 1 allspice, 1 lime and ¼ syrup. By volume, the Brandy Crusta is 62% spirit, 17% citrus, 15% liqueur and 6% syrup and sugar; the Lion’s Tail is 63% spirit, 16% liqueur, 16% citrus and 5% syrup and sugar. That makes them close cousins on the ratio map.
The Brandy Crusta is the stronger drink in the glass (20.7% ABV against 18.3%), but the Lion’s Tail is the bigger drink, so it holds more alcohol (1.73 standard drinks against 1.47). The Lion’s Tail has more calories (about 204 against 171) and more sugar (7.8 g against 6.3 g). Both are served in a coupe; the Brandy Crusta is stirred, the Lion’s Tail shaken.