A modular assembly for supporting fiber optic splices includes a tray, cradle, and splice holder. The tray includes a floor, a depression in the floor, and a tab that extends outward from a depression sidewall into the depression. The cradle includes a base configured to be seated in the depression. The cradle base has a first face positioned away from a bottom of the depression and an opposite second face positioned towards the depression bottom when the cradle base is seated in the depression. The cradle base also includes a shelf recessed into the first face at the first side of the cradle base, and positioned between the depression bottom and the tab when the cradle base is seated in the depression. A splice holder is mounted to the first face of the cradle base and defines a plurality of fiber optic splice slots positioned over the depression.