I've also had difficulty seeing the ball as the sun sets. Our courts are surrounded by trees. In the early evening the sun glints off the leaves making thousands of little "optic yellow" dots even through our fence with black mesh. Shots that go high often blend into this background and the ball becomes just another yellow-green dot among many.
Pure Storm GT: 11.9 oz., 8.5 HL, SW 325
VS Touch Black/Focus Hex 1.23 @ 58/54