There aren't any formal nights on Norwegian cruises, at least in the classical sense. They may have a specific dining room designated for formal dress on one or two nights, but there is no need to even pack formal wear. And remember, in Hawaii a tropical shirt is considered formal attire.
I've not sailed on the Pride Of America. Have you ever looked at Cruise Clues? It is a website put together by some old friends of our forum and I see they still maintain it. Tons of info about all ships. Some is dated, but some is new. Check it out here