Great Manhattan variation. Hayman's "slow" gin really mellows the spirituous Whistle Pig PiggyBack rye, which is only 96.56 proof according to the bottle but 100% rye. Difford's 3:2 proportions are about right with these ingredients. And as The Man Behind The Bar I was careful to use Nick & Nora's as you stressed; Kristi says we should watch "Thin Man" movies while sipping these.
Whistle pig might be a happy medium re abv. I had local Gospel rye this evening at 42.5 abv, bumped to 50ml. It was slightly struggling to keep up with the other ingredients, tho overall still VERY delicious cocktail. Will def be playing with this some more!