There are many ways to solve the engineering problems in airplane design.
I am not familiar with the technical details of the triple-seven and don't have any manuals handy but I can give you some general info. It has been a long-standing Boeing practice to use inboard and outboard ailerons. The outers would have more authority at the same amount of throw (deflection) as the inners because they are farther from the CG. More leverage. In fact, at high speed they have too much authority. And so, at high speeds, Boeing designs use the inboard ailerons and roll spoilers for roll control. The outboard ailerons fair to neutral with flap retraction.
Like many other airplanes including the DeHavilland of Canada ones, the ailerons droop with flap extension. They contribute to the production of lift at low speeds but still function in roll control.
Airbus and Boeing alike use roll spoilers for primary roll control at high speed/mach number.
In some early high-speed airplane designs there was a problem with the ailerons twisting the wing at very high speeds with the resultant high dynamic air loads. Friends have told me that the pilot checkout in the B-47 (and the B-52 also, I believe) included "aeroelasticity" demonstrations where the IP would put the plane in high speed low altitude flight, then roll the yoke laterally from stop to stop. The plane would continue straight ahead and the wings would twist. (of course they did not hold it to the stops for very long)
Roll spoilers address this problem. Typically, yoke input in the high speed regime deflects roll spoilers only until a sufficient amount of roll is called for, then the ailerons begin to operate.
Happiness is not seeing another trite Ste. Maarten photo all week long.