Curated to provide instructions, which are an educated guess right now.

Made with El Dorado 12 year rum, this is one of my favorite drinks of all time. I made this at my brother-in-law's wedding reception, and it was a huge hit.

Banks 5 Island and black sage honey make for a flavorful and summery drink. Can also be made with lemon. An Airmail without the sparkling wine is called a Honeysuckle (also a good drink).

If you replace the honey syrup with domaine de canton it's called a China Post; if you replace it w/ st germain it's a Poste Aérienne. Both are fun variations

PDT cocktail book attributes this to W.C. Whitfield (Here’s How, 1941). Other sources say first appears in Esquire’s 1949 Handbook for Hosts. Anyone know which is correct? Either way, it clearly predates posted attribution. 

It is included in Here's How on page 36.  It has the earlier of the two publication dates you give. I have no clue if this was the first place that it was printed though.

That first ingredient should be an American Gin, not vermouth.
Hess used Voyager brand Gin in his Small Screen Network video.

Updated. Thanks.

enjoyed, and as a Campari fan, i found this to be well balanced...

Not an amaretto fan, and this drink did nothing to change that. It is, however, a very nice Martini variant without the amaretto. I don't understand the appeal of the almond cookie flavor of amaretto with the bright citrus of Campari. I would think that Cynar would be a bit more harmonious. Made with Luxardo amaretto and Dolin dry.

Made it with Bombay Sapphire, DisAronno and Cocchi Americano. Unbalanced. Probably better with a bolder gin, like Beefeater. Might need a milder vermouth, too.

I used Cynar instead of Campari and Lillet Blanc instead of dry vermouth and it was pretty good

I liked it, found it to be pretty well balanced as a campari fan. I've been looking for more dry vermouth cocktails and this is one of my favorites so far.

Surprisingly fun template to play with. I enjoyed both Campari and Cynar variants. Would like to try Amer Picon here in the future.

Like several others who commented on this drink, I also found the "Venetian" to be a tasty and enjoyable drink. Unlike Dan, I enjoy the taste of Amaretto, but only if it's in the background enough so that the drink is not too sweet and the other ingredients are not overwhelmed. Fortunately, the drink was not too sweet and the other ingredients held their own.

Along with Campari and Disaronno, I used Tanqueray Ten gin (which can hold its own) and I paired it with a dry Spanish vermouth that is infused with unspecified herbs (my 1st use of this vermouth, and it worked well in this drink). For those interested in this unique vermouth, the company's name is Priorat Natur and the product is simply named Vermut. It is light brown in color and is bottled at 32 proof. If you like to explore vermouths (and are looking for a unique dry vermouth), I recommend this one. I paid $26 (in Michigan). By the way, I rated the "Venetian" at 4.0.

A nice, refreshing summery cocktail. A bit more lemon takes the sweet edge off for those that prefer a tarter balance. 1 1/4 oz is nicely tart. 1 oz would probably be popular.

Pleasant. Added 5 more dashes of Peychaud's, which I think really wakes it up, balancing the strong St. Germain flavor.

Attributed to Dave Wondrich. Created for the Jakewalk bar in Brooklyn, NY

Only had blanco tequila and used a heavy hand with the Peychaud's, good stuff. I'd maybe add some orange bitters next time, but I think that goes in everything.