I think that a single 525/XR package would be the way to go to keep the boat affordable, plus it would show strong performance numbers.
The 525/NXT might be a great option, however prop availability (cleaver) may still be limited for a single application. Could take time to get it dialed in given that... I would say it depends on how much time you have to get it out the door.
Ten years ago we didnt have dependable power and drive packages that could push heavy single engine 28-32 footers at decent speeds. Twins were the only way to get there. Technology has brought about some great single Offshore options.