up is up - tilting away from the transom, raising the prop and drive (lowering the nose of the motor), angling the prop up, which would push more on the stern, lifting the bow. down is tilting in toward the transom, lowering the prop and drive, angling the prop down, lifting the stern and lowering the bow.
when you take off, all the way down, as you come on plane, raise it up until the boat starts to porpoise, then bring it back down a slight bit. if you have more weight in the bow area, you may need to trim up a bit more. on my boat with the stringer drive and the prop I was running, the happy place on plane was between 1/4 up and 3/8 up unless we were fishing on lake erie, then with the extra weight in the front, it was up about 5/8 the way.
