We brought the lemon up to nearly 1/2 oz in order to cut down on the sweetness, and it turned out to be the right call. Tried it with both white rum and aged rum, and both were nice in their own way.
Used Ron del Barrilito and Cocchi. This was as complex as advertised, and less sweet than I had anticipated. Nice to have a Manhattan variation that's a little lower ABV and more tropical in the mix.
I went with Cocchi Dopo Teatro vermouth amaro in lieu of regular sweet vermouth in the hopes of cutting down on the sweetness and raising the complexity level. I'd make that substitution again.