Tried with Cinzano Extra Dry and the result is very good.
Really enjoyable and nice to drink, the proportions are perfect in my opinion, the cassis shines like sunlight through clouds for vermouth and the lemon oils get their part as well. Lovely.
On a second taste, 3 months later, I would say that the cassis shines a bit too much for me in the start before the ice starts to melt.
I wouldn't add more Vermouth but perhaps a small amount (0.25oz to not more then 0.5oz) of acid or something. But on the other hand I'm not sure I want to brighten it too much...
Really enjoyable and nice to drink, the proportions are perfect in my opinion, the cassis shines like sunlight through clouds for vermouth and the lemon oils get their part as well. Lovely.