When I couldn't get the Benedictine I read the Yello Ch was the option, but not really. Here both together turns is a little bitter. It needs something else: so I am gonna divide my cocktail in two.
The first half I put some sugar -allulose on it. Lovely, the bitternes is out, and is perfectly delicious.
Now the 2nd, I put the proverbial salt described in the comments. Is completely different, but the effect is the same: no bitter. The salt make it round and oddly enough even sweet.
In order strange better than common: the salt is the quid of the question:
FUTURE GUS: do this with a pinch of salt.

Unlike a few Discerning Drinkers below, I definitely prefer to keep this drink equal parts. I really enjoyed how honey-forward it is, with the lemon to tame the sweetness and the herbal complexity to play against. Highly recommended.

1oz Bombay gin, .75oz Benedictine D.O.M, .75oz Génépy, .5oz lemon juice, 2 drops saline (will do 1 drop next time... almost salty).

Killer cocktail! I've made equal parts version multiple times, but this slight adjustment will be my go-to version.

I used Plymouth Navy strength gin and a tiny pinch of kosher salt and wow, this is an incredible cocktail. The interplay of the two monastic liqueurs and the lemon juice is sublime with the gin bringing a nice backbone.

With both Simon and a number of experienced drinkers rating this highly, I may be sticking my neck out a little by suggesting a small adjustment that worked better for me.
I found the following ratios more balanced:
37.5 ml gin
15 ml Yellow Chartreuse
15 ml Bénédictine
22.5 ml lemon
In this more spirit-forward build, the gin clearly leads. The Chartreuse is present but controlled, while the Bénédictine adds a subtle honeyed background note. The lemon brings brightness without tipping into excess acidity.
Just sharing in case it’s helpful to anyone experimenting with the balance.

I wouldn't use subs here. Strega and Drambuie left me wanting the call ingredients. Tried it twice, leaving the lemon measure as is, and 25:20:15 with the spiritous elements left a more approachable taste, but not quite balanced. Ran out of the Benebuie, so I'll have to wait to dial in the delivery.

Very well balanced drink overall, and one of my favorites. For a more citrusy profile, I use Citadelle gin. Though I love the sweetness in Chartreuse Jaune, Chartreuse Verte adds a much more herbal backbone and accents the juniper notes in gin.

This for me was an all encompassing lemon bomb. Might try again with half the lemon juice. Also I used Dolin Génépy. Perhaps Chartreuse Jaune is more assertive here.

Really tasty/tart/lemony drink! 2 drops saline will tone down the sweetness.

Some drops of saline solution add a nice extra. My next try will be Japanese Umami bitters.