Two rings made with scraps very seldom end up the same size. However, since they are made from two wires twisted together, they are easy to stretch out a bit.
Place the larger of the two on a bezel, ring, or hoop mandrel (used here). Use an ultra fine point Sharpie to draw a line on the mandrel just below the twisted wire ring. Remove the ring and replace it with the smaller one. Sometimes all that is needed to stretch it out a bit is pushing the ring down mandrel with your fingers. A rawhide mallet can also be used to help stretch the ring out a bit. Be careful when tapping the twisted wire ring, though. It stretches VERY quickly.