Perhaps you question is part answered by the considering the aerodynamics of ailerons.
For any given size aileron the further out from the fuselage it is the more effective it becomes.
Put another way for a full span strip aileron the outer 1/3 provides 2/3 of the effect, however the drag it creates when it is deflected is more or less constant along its full length.
From this you can see that a 1/3 span aileron mounted from the wing tip is more 'efficient' in doing what it does although a full span strip aileron will be that bit more powerful.
So where aerodynamic efficiency is important (eg a glider) limited length ailerons mounted at the wing tip are used. On a plane intended for 'full house' aerobatics full span ailerons are used. This applies to full size as well as models.
Of course if you want a plane to 'prop hang' the ailerons must go right up to the fuselage to provide control purely from the prop wash.
There are of course issues of the construction of the aileron and how it is moved that can influence their size and how they are mounted.
I hope this helps.