Selflessly (selflessly, I tell you) testing and retesting small variations on this most excellent summer afternoon cocktail, I can finally report that:
the dash of creole bitters is vital // the swapping out of 5ml of (even) the very tasty Belle de Brillet pear liqueur for 5ml of the Massenez Poire William eau-de-vie still lifts this drink to another level // increasing the bitters and/or the eau-de-vie do not improve the drink // if you need one (or two) quickly, rinse the ice cubes to smooth the surface to reduce fizzing and making the cider go flat.
// Santé à tous !

[Bubbly Belle], added my personal recipes as [La Vie et Belle] (sic !)