You may want to try and find a performance bulletin on your boat and it will usually state the motor and cavitation plate height setting.

 

w the plate down and the motor level go 1" below the center keel line, this will keep you out of trouble w rough water and cavitation

 

Those boats were built to have the transom bracket all the way down on the transom I would put the plate so it is even with top on the transom and the engine all the way down it will perform a little better with the set back but u wont be able to run it up much at wot