Hi K. Frank,
thank you for your answer 
I will probably just go for the first approach, since I’m short one time, but I will give the second one a try as well, simply because I think it would be a good exercise.
Just to make sure, I understand that approach correctly. One way to achieve this would be to apply a mask to the wings gradients, which zeros every 2nd gradient for the wings (similar to here). Essentially doing manual dilation, right ?