I'm going to be a party pooper, but I'm just stating my opinion. I think the tank is so cardinal dominant, that the rest of the species, barring perhaps the rainbows, are a moot point. I also that in a 400lt tank, you're not going to even see sparking gouramis most of the time. There are three varieties often marketed as "sparkling" or "croaking" gouramis. Trichopsis pumulis is the smallest at 4cm. Trichopsis shalleri has a more defined red lining to the fins and gets up to 5cm. T. shalleri is the prettiest, IMO. Even larger is Trichopsis vittatus, which gets up to 7cm. T. vittatus has a prominent "eye" spot right behind its gill plate, and the anal fin is lined with a thin band of white. Otherwise these species are often mixed up in the shops. T. vittatus will have the best chance of showing up in a larger tank. All three, and this is from my own experience, eat chrimp with much gusto!
Sorry, just my two cents worth.