Yamaha GP 760 Porpoising

I have a pair of 97 Yamaha GP760s that my wife refers to as :the twins" I would like to know how how I can eliminate porpoising of these boats. What effect would replacing the stock steering nozzel with an extended one have? 
​Eric

Eric,
Extended steering nozzles would indeed help reduce the tendency for a craft to "porpoise"... as would an extended ride plate. however, I believe the GPs have adjustable trim positioning on the left handlebar that should be able to set to a more comfortable ride. Trim "down" for take off, especially with havier loads, such as kids and/ coolers on back. and "trim "up"  once underway for speed and less drag on the PWC. If " porpoising" present, go one "click" down at a time until smooth riding.
​Tech Talk