Here are my Brooklyn experiments from last Thursday. I used Bulleit for the rye and Noilly Prat for the dry vermouth.
On the left, the dry vermouth-heavy version: 2 oz rye, 0.25 Picon, 0.5 oz dry vermouth, 0.25 oz maraschino liqueur. This is similar to Difford's but with the rye increased from 1.5 to 2 oz.
On the right, the Picon-heavy version: 2 oz rye, 0.5 Picon, 0.25 oz dry vermouth, 0.25 oz maraschino liqueur. This is the version from the Bartender's Choice app that I've been using lately.
The first version is drier and feels a little bit lighter. More crisp. The second version is more rounded and has a fuller flavor. They both work but the second one is my first pick because it accentuates the flavor of the Picon and makes a more distinctive cocktail.