Many make this drink with 30ml amaretto and 15ml dry vermouth and, as you'd expect, the result is sweet with amaretto predominating. This 2013 formula...
I learned this cocktail early in my career (c. 2008?) as being made with Canadian whisky, which I think often pales. My preferred recipe uses a mix of Canadian and Rittenhouse PA-style rye... with equal parts dry and amaretto... orange bitters (or bartender's choice), plus cherry and orange garnish. The proof (and dryness) of the whiskey makes a huge difference in how this drink plays.