Just tried sour-ifying this with 1/2 oz citrus (I used yuzu super juice) and like it better. Spice, lime, Hawaiian Punch.

Vermouth bianco & Aquavit go together surprisingly well. We used the full amount of vermouth. I’m not sure why the drink should be in a wine glass. In any case, it is a tasty little drink.

The wine glass was adopted wholesale from the vintage recipe for the Balaklava Special No. 1, on which this drink is a riff. (Instead of grape-based spirit [cognac] and caraway-inflected mixer [kümmel], this uses a caraway-inflected spirit (aquavit) and a grape-based mixer [vermouth].)
But it's not particularly important for the enjoyment of the drink that it sticks to the original glassware spec!
Glad you liked it!

Gave it a dry shake and served it up. Very tasty. I like how the woodsy bitter cherry flavor of the Amargo Vallet works with the lemon juice.

Also works well with 1/4 chartreuse for those who aren't fans. I added the remaining bsp of fernet and it gave the expected minty oomph that was also a nice variation

Great name, Big Guy!

Okay, but Muisca Sour is a better version.

A solid drink - very vanilla heavy and fairly sweet.

Felt balanced with anejo. Gorgeous color in the glass

A little too vanilla forward for my taste but balanced nonetheless.

Used maraschino and fernet from Leopold Bros., homemade cacao, Xocolatl bitters, and Fundador brandy. Very good stuff. This brand of fernet overpowered some, would prob do 3/4 and/or increase the maraschino.

Higher math was always a stumbling block, so I was hesitant to try "Silvio's Algorithm." Until I looked at the ingredients, that is! I knew from the beginning that this drink was the Drinker's Drink. And the proof was in the pudding, as it were.

I used Bols Genever Amsterdam gin--barrel-aged as specified, Angel's Envey, a good, but not well known bourbon--this batch distilled in port wine barrels at 86.6 proof, a skinney Fernet Branca, Aperol, and Amaro Meletti. And lemon zest, to finish it off. This is an incredibly smooth drink. The Meletti is there, as is the Aperol. Both provide a slight but necessary bitterness. The Genever gin sits quietly in the background, giving room for the bourbon to speak up, but softly so. And the lemon zest is a necessary must, to round out the flavors.

There is a lot of alcohol in this drink, so plan accordingly. Two of these says get an alternate driver! But this drink is like a potato chip; it's hard to stop with one. So enjoy, but be careful. I rate "Silvio's Algorithim at a well-deserved 5.0.

Used St. George Dry Rye Reposado for fear that an Old Tom might be too sweet.  The result felt a little too astringent.  Would try Genever next time around.