I recently read a comment on another site from someone whose grandfather bartended at the DAC in (I believe) the 1930s, and the version served at the time was 2:1:1:1, single strained. This makes the recipe above (2:1:1:1 + water, double-strained) the closest reproduction that doesn't leave you with ice chips in your drink. Many thanks for brining it to light!

I've tried a few configurations and found that with real Chartreuse, I prefer the moodier, more herbaceous, and slightly heavier version presented here; with Dolin Genepy, I prefer equal portions with no added water (which I find lighter, brighter, and perfectly balanced). Either way, it's a truly spectacular cocktail, and I wouldn't even describe myself as a gin enthusiast (though this drink is starting to make me reconsider my position)!