Lovely indeed!
Used gin, dialed down the elderflower to the same amount as the aperitivo (for which I used Cynar), and added about 3.5 ml of Malört to bump up the grapefruit flavor and add some indefinable intrigue.
Garnished with a nasturtium flower because it's summer and I have a lot of them :)

I agree with your assessment about the balance! We thought it would be good with a splash of Malört, which might not be too different than grapefruit bitters. I'll give a full report after trying it out today 🤞

Made it exactly according to the recipe and loved it!
Less sweet and more interesting than the typical Old Fashioned. The Amontillado anchors it with a nice mushroom funk, and the lemon gives it an elegant, refreshing lift.
5 Stars!

Excellent!
I substituted tart cherry concentrate for the cherry liqueur, increased the tequila to 60 ml and bumped up the lime juice a titch.
It's like a margarita and a bomb pop had a baby! :)