Your Ducky came with windowed keys. Obviously those are best but if you wish to replace them with opaque keys, ABS is supposed to be better than PBT because they let more light through. Based on photos I've seen, it looks like the POM keys will also let a lot of light through. Obviously white is better than black or other dark color. So if you must, look for a set of white doubleshots or blanks. There's also crystal keys (clear). They would really light up, but I don't know how attractive they would be.