Nice set up so far. I love the rainbows but they can be quite costly! If you decide to go that route Roseline17 on aquabid has some of the nicest rainbows you've ever seen, have some from him that grown into beautiful fish. My two cents is that you generally want to break up the background with at least one other variety with some height, something to cover that overflow. That corymbosa in the back will grow like a weed and you'll be cutting it nonstop, at least that's been my experience. The stalks get thick and the bottom leaves fall off and then they become very tree like, mine were breaking the surface of the water every week. From what I've read you can keep trimming back the tops to encourage more leafy growth but I never got around to it. Are you dosing micros and macros?
Jack of all trades.... ... .. . master of none.