The pitching moment caused by the thrust line is exactly like turning a bolt with a wrench. Think of your hand as the motor, the wrench as the pylon, and the center of gravity as the bolt. By looking at it this way you can see that an engine on a pylon directly over the CG is the worst case. You can not fix this by tilting the motor. The only thing on an airplane that can counter the pitching moment from this is the horizontal stabilizer. Making the HS that you have won't be very effective during takeoff because there's not much airflow over it yet. What you need to do is strengthen the vertical fin and move the horizontal up int the prop wash.