[Fr. Frank]

If you really want to see what she'll do at WOT, trim the engine out until the prop starts to ventilate/break free, then you'll know when you've gone too far.

Wait 'til you're at WOT before you start trimming out for max trim angle, as the max trim angle will be different at different speeds. Once the prop starts to ventilate, just tuck the motor down a bit 'til you feel it/hear it bite fully once more. If you're using a steering cable. instead of hydraulics, steering at proper trim will be neutral with no pull to either side (assuming you're using a factory torque tab behind the prop that is positioned properly)