The 427 should be good. You could cut a 430 an it would be good too. IMO you will find the 400 series props will handle significantly better; especially with a narrow beam hull.
Kelly's point about the 35 mm prop being a reasonable limit is a real one. Smaller props do not upset the handling as much and you will find the baot can run very quickly.
The motor is hot for Offshore but only just if your prop gives you 4.5 minutes runtime on GP3300 - and it should - at that pace that motor will be working at maximum efficeincy and optmum output.
gearboxes are used because the motor is too revvy - keep your controller advance low and it should be fine.
