I did this on my P-51. I used plastic hinges. In hinde site, I could have used ca hinges since its a 60 sized mustang. I wouldnt use ca hinges on anything over 60 sized, just my opinion. The wing hinge line is straight. The leading edge of the aileron is cut back at an angle to give me about 30deg of deflection. Thats max throw, I never use that much, just wanted to have it. At the top of the ailerson I left myself about 3/16" to cut the hinge slot then hand sanded a bevel on both sides of the hinge line. Works great, no problem, no different than center hingeing.
Edwin