3 parts dry vermouth to 1 part 1:1/50°Brix simple (or other syrup) is akin to blanc vermouth in sugar content. Yes, this combination is more bitter than a Negroni, but dropping the sugar content will only make that aspect more intense.
Isn't this essentially Eeyore's Requiem from Toby Maloney at the Violet Hour? This one has an extra 1/4 oz of Cynar but otherwise reads like the page in 2011's Beta Cocktails.