With both Simon and a number of experienced drinkers rating this highly, I may be sticking my neck out a little by suggesting a small adjustment that worked better for me.
I found the following ratios more balanced:
37.5 ml gin
15 ml Yellow Chartreuse
15 ml Bénédictine
22.5 ml lemon
In this more spirit-forward build, the gin clearly leads. The Chartreuse is present but controlled, while the Bénédictine adds a subtle honeyed background note. The lemon brings brightness without tipping into excess acidity.
Just sharing in case it’s helpful to anyone experimenting with the balance.

I tried a very simple build using 50 ml Avallen Calvados, 15 ml fresh lemon juice, 12.5 ml homemade grenadine (fresh pomegranate, pomegranate molasses, sugar, orange blossom) and a dash of orange bitters.

With a dry, clean apple brandy and a proper grenadine, I found extra syrups unnecessary. This version keeps the drink bright and dry, lets the apple and pomegranate speak clearly, and stays true to the core of the Jack Rose rather than polishing it into something sweeter.

This ones a winner.:
60ml Diplomattico Mantuano,
15ml Bénédictine D.O.M. Liqueur,
15ml Giffard Créme de Cacao Brown Liqueur,
2 drops Ancho Reyes Chile Liqueur (homemade)
Between sips - A piece of 70% Cacao Fino de Aroma from Colombia

I like dessert cocktails, and I like strawberries, and cream, and chocolate, and gin. No surprise then, I think this is yummy .