Line both trays with parchment. Combine the coconut with all but 2 tablespoons of the measured condensed milk. Rest for 2 minutes, then squeeze a spoonful. Add the reserved milk 1 tablespoon at a time if the filling crumbles. If it still feels dry, add extra milk 1 teaspoon at a time, up to 1 tablespoon. If the filling slumps, add up to 2 tablespoons extra coconut, 1 tablespoon at a time.

Divide into 16 portions. Firmly press each into a bar about 2½ inches long and 1 inch wide with rounded ends and a slightly flattened base. Arrange on one lined tray. Freeze for about 40 minutes, until the centers lift without bending. If they still bend, freeze for 10 more minutes and check again.

In the dry microwave-safe bowl, heat the wafers at 50% power for 30 seconds. Stir and continue at the same power in 15-second bursts, stirring after each, until smooth.

Working with three or four centers at a time, keep the rest in the freezer. Dip each bar with the two forks, tap off excess coating, and transfer to the second lined tray.

Refrigerate for about 20 minutes, until the shells feel firm and the bars lift cleanly from the parchment.