Wow, they are beautiful. I plan on getting a pair of spectrals soon and I also would be thrilled to breed them. What does your enclosure look like because I really need some inspiration on how I'm gonna set mine up.
Some of them have been eating small mealworms from a cup, but I also dump in fruit flies, bean beetles, crickets, dubia roaches, etc. and I've seen at least one of them eating all of the aforementioned insects at some point so far. I've also found tapeworms in their feces, so keep an eye out for parasites with your spectrals as well.