The situation is entirely symmetrical so we need consider only one of the masses. His space is dilated so the test mass has further to fall. His time is dilated so there is less time for the test mass to fall. The test mass starts out with a rest mass greater than 1000kg and when it arrives this has fallen to 1000kg. Because of the greater distance he perceives, and because his perception of the Earth s gravitational field is greater, he will also perceive a greater terminal velocity and kinetic energy than A .
Light behaves the same way.
Light falling down onto the Earth s surface is blue-shifted since it increases in energy. Light leaving the Earth s surface is red-shifted. They are manipulated as field equations even though they are a spatial distortion. By inference they may exhibit other electromagnetic phenomena, such as radiated waves. So an oscillating mass might generate a freely-radiating gravitational distortion.