JV,
I'm an engineer not a pilot but I can only echo Lomcevak's opinion as far as the role of the Horizontal Stab and Spoilers in a modern aircraft. As you're well aware, in either a FBW aircraft or whenever the Autopilot is engaged on one with conventional controls, the elevator loads will be faded out by moving the Stab. Roll control can use spoilers to offset or augment elevators at angles as low as around 8 degrees - to the extent that the Autopilot can have difficulty coping with the non-linearity - much lower than in the 747.