This thread includes the saga I went through with a hooked hull because of incorrectly assembled floorboards that failed to stretch out the hull fabric.
http://www.rib.net/forum/f50/cav-pla...mk4-53656.html
Waaaaay, too much time and effort was focused on the height of the motor in relation to the transom. In fact, on the advice of my dealer, I had a steel plate added to my transom to raise the motor several inches and that just caused a new problem: ventilation (with the AV plate about 1 inch below the bottom of the transom).
After getting rid of that modification and just assembling the floorboards correctly, my boat runs perfectly.