I agree with Mike & Island shark. Keep it simple. Largest Tile fish, largest Grouper (any species). Manual or Electric does not matter (far too difficult to monitor that). Two fish = two prizes.
I also agree with Catch. There shold be some sort of contribution / entry fee to cover any expenses.
Mike - Lets have a gathering / captains meeting at some convenient location to iron out the details. Those of you outside the US will have to post your suggestions. Or maybe we could have the meting conveninetly located at Bottle Bay