Best of luck and I hope it works out for you.
The reason I have some basic knowledge is that I get about 18% slip which to my mind is still too high so I have looked at ways to reduce it. I have raised my motor one hole (which helped me get another 200 rpm) and would like to go another but that would mean a jack plate or redrilling the transom which I dont want to do.
Have a look at this link regarding prop height.
My thoughts are that if your Anti Cav plate is level with the bottom of your hull it is too low but it does vary from hull to hull. The further back (set back) your prop is the higher it can go.
Any chance of a picture of this strengthening strip, I wonder if that is causing turbulence just in front of the prop.
And finally do have a look at the Prop Gods forum. It is USA based but the advice on prop selection type, diameter and pitch is the best around
Good luck again