Honey syrup and grilled lemons mix with tequila for a perfectly balanced sweet-and-sour marg.
In a small saucepan, heat the honey and 1/2 cup water over medium, stirring, just until the honey dissolves. Transfer to a bowl and let cool for about 30 minutes.
Heat a grill or a dry skillet to medium-high. Working in batches if needed, place the cut sides of the lemon halves on the hot grill or skillet. Cook until the flesh is browned, about 6 minutes. Transfer to a plate and let cool to room temperature. Grill 1 side of each lemon wheel until the flesh is browned, about 6 minutes. Transfer to another plate. Juice the lemon halves into a large liquid measuring cup. Halve and juice the remaining whole lemon into the measuring cup. Pour 1 1/2 cups plus 2 tbsp. of the juice into a large pitcher. Stir in the tequila and the honey syrup. (If not serving right away, cover and refrigerate for up to 2 hours.)
Stir the cocktail. Fill the pitcher with ice and stir until the outside of the pitcher is cold. Pour into glasses filled with ice. Top each drink with a pinch of salt. Top with a lemon wheel, grilled-side up.