Wow, I haven't seen that problem here before. I would be inclined to get that closer with metal before you use filler there. That is a real bad spot for building up with filler only. You might try using wire with the same radius as the edge you need to form the contour and welding it in and shaping it as close as you can first. don't use too much heat!
Edit: I didn't notice the wave in the body line! Was that there before you hung the skin?
Edit #2 I see, the "Wave" was just camera angle.