Sometimes I feel like the comments and the drink just don't match at all and this is one of those times. That probably means that it varies a lot based on what you use so just for reference I used West Cork Black Label, Perlino Vermouth, De Kuyper Apricot and Cynar. I don't feel that the drink is too sweet at all compared to something like a Manhattan. The Cynar brings out some really interesting flavours from the Apricot liqueur. The Whiskey is there to provide some buttery and charred notes.
Was concerned that sweet vermouth would overpower/mask the Irish whiskey & liqueur*, so I subbed Bianco**. To my taste, Cynar was a bit too forward so I subbed Nonino on my 2nd go at it. Adding a smidge of verjus brought it to life. Will use my riff as a template with other liqueurs***.
* Sexton, in my case
** Vittore, in my case
*** indeed, I used this as a template with Menaud Camerise. It's not terribly sweet, so I upped it to 3/4 oz to to bring the fruit forward. Cocktail was moreish :)
I used proportions as per the recipe and found it spirit-forward rather than sweet, so it may depend on your whiskey/vermouth/apricot brandy combination.
Used Bushmills and followed Chris Brislawn's advice and upped to 1 3/4 oz. Originally found it a bit too sweet and the additional whiskey helped. Found it very nice for an evening cocktail.
I was also worried that the proportions looked a bit sweet so upped the Irish (Dunville Three Crowns) to 1 3/4 oz. A healthy squeeze of lemon zest helps, too. Used Drillaud Apricot liqueur and Carpano Classico Rosso. The Dunville meshed nicely with the other flavors without getting lost and the Cynar kept it bracing. A winner.