Yeah, you can do it that way. I think it's actually easier to cut the hinge slots in them before you sand the bevel.

Draw a centerline down the LE of the ailerons. Cut the slots for your CA hinges or DuBro flat pinned hinges. Or, if your using Robarts, drill your holes and get the countersink to the right depth for a good fit.

When your done with cutting the hinge slots or drilling the holes, sand down to the line you drew on the centerline. Done. Now mock up your control horns and make sure they solid and mounted where you need them. Remove the control horns.

You can sand the TE of the ailerons if you want. I always just left them the stock thickness.

Your ready to cover the ailerons now.