This is my most flown plane, and one of my favourites, also with a saito 56. Make sure you have your wings lined up correctly and that you are balancing it right. I think that this plane does lift a lot due to the flat bottomed airfoil, I trim mine at 1/2 throttle and it is a baby to fly. I will say though that it is the only plane that I have ever had that I have to retrim almost every flight due to slight changes in the configuration of the wings when I transport it or hang it up, just minor but it happens. I have not known anyone have to modify this plane to make it fly as per instructions. I would adjust the elevator with a little more down in it if the cg and everything is right, then fly it and retrim, once it is trimmed it does fly great. Make sure your rudder is centered well too.
Good Luck
Paul