Adding Ailerons

[Battfly]

I'm adding ailerons to an old glider wing. The wing is not a flat bottom, but actually concave. My question is about the angle of the added aileron, should I line it up with a (imagined) line from leading to trailing edge, or follow the curvature of the wing ( which would aim the aileron downward)?
I know from experience with a flying wing that you need to line up the aileron with the bottom of the wing for neutral trim. I don't know how to handle this wing shape. The wing looks like an Ascent wing from the side

Thanks for any help.

[Ollie]

The aileron is part of the airfoil. If you intend to just add ailerons without changing the airfoil, then the airfoil contour after adding ailerons should be exactly the same as before when the aileron is at neutral, except for the necessary notch at the hinge line to allow the aileron to move.