Antoni, the recipe has just the one (not two) amaro. And to our taste, there is really no satisfactory substitute for Nonino Quintessentia. If pushed hard, we might substitute Amaro Nardini or, at a pinch, Ramazzotti but not the Sicilian Averna. While the comments here on this website are proof perfect that discerning drinkers abound, there is no such thing as a discerning AI. Better to trust to trial and error with your own taste buds. Cheers.