For the TRIM ALONE to give you bow lift of any degree the anti vent plate (the horizontal plate just above the prop's blades) has to be in the water, not "at" the water's surface or above it. It needs to be low so that the front of it can "dig" into the water as you trim out.
Get your boat out and get it running around the speed you use when skiing, set the trim to 0 degrees (perpendicular to the hull) and get some one else to drive for you. Go back and being careful to grab on to something solid, look over the transom at the water running past the lower unit. The AV plate should be about an inch below that water surface. Then trim to suit and expect reasonable bow lift. With the engine in this position, you have 2 forces working for you, the bow lifting action occurring as you trim out....making the engine dig in deeper, pulling the transom down, and the thrust vector from the prop wash. If the AV plate is above the water's surface, you have thrust vector alone and I guarantee you, that is a whole lot less of an effect.
Now how do you suppose I know what I just said? BTDT and accidentally discovered it when raising my engine (on one boat) to get less drag and higher speed. All of a sudden I lost trim sensitivity. Where I could trim in and out and have noticeable bow movement as I did it, with the engine jacked up and the plate out of the water, I had a lot less control on the bow lift, and a lot less of it causing more drag and slowing the boat. That is when I put on a bow lifting SS prop with high RAKE and solved that problem and got more speed too. This was not on my skiing boat as that boat came many years earlier and had no trim......before OMC put trim, or tilt for that matter on it's (1972) 125 Johnson (biggest they made at the time, or any other of their engines).
