This recipe is a broad interpretation of Jacob A. Didier's 1909 original and the Casino recipes that follow in Hugo R. Ensslin's 1916 book and other subsequent...
Didn't have Old Tom, but use The Botanist Islay Gin. It was wonderful. Nice balance to the cocktail. Did follow the advice, and sip and swill in my mouth. It gives it a spice, pepper flavour just drinking doesn't release. Very good cocktail.
Built with Bombay blue sapphire otherwise as prescribed. It was a bit tart but tasty. I might cut back on the lemon a bit say 1/4 to 1/3 oz and replace with a bit more gin. Overall quite tasty and would recommend it to a friend.
My go to Gin is Pinnacle Gin for mixed cocktails and it has a slightly more tempered taste so that might work as well.