Yes, you’re right on this so use a decent Cremant from either Alsace, Bourgogne or Loire. Or a Blanquette de Limoux; all using the méthode traditionnelle but can’t be called champagne because of the AOP. I can only comment on French regional ones because I know them best.
If not any other good quality sparkling white wine would not ruin you’re cocktail.
If not any other good quality sparkling white wine would not ruin you’re cocktail.