For least drag, if you are going to have a V notch for the aileron hinge line its better to have that at the bottom (and it looks better when the plane is on the ground)
Best is to use the centered hinge behind the front of the control surface, round the surface and carry the wing's top and bottom back to meet it.
See step 5.. carry the hinge point back into the surface a bit extra.
Use thin (1/64) aircraft ply or aluminum to carry the top and bottom wing surfaces back to brush the control surface, closing the gap..
The difference in drag vs the hinge at the bottom is not large... especially at our size and airspeed of most sport-scale models.