Yuzu Kosho Deviled Eggs

Name: Yuzu Kosho Deviled Eggs
Ingredients: 2 Tbsp. Champagne vinegar or white wine vinegar; 1 tsp. sugar; 2 tsp. finely chopped shallot; 3 small radishes, trimmed, very thinly sliced; 18 large eggs; Kosher salt; 1 Tbsp. S&B hot mustard powder or 1 Tbsp. plus 1½ tsp. Colman’s mustard powder; 1 large egg yolk*; 2 Tbsp. fresh lime juice; 1 Tbsp. (or more) green yuzu kosho; 1 cup grapeseed oil or vegetable oil; 2 tsp. finely chopped cornichon; 2 Tbsp. finely chopped tender herbs (such as parsley, chives, shiso, or chervil), plus more for serving