Jim, what are you referring to when you say "replace the whole top wing panel over the tank bays?" Do you mean going all the way to the trailing edge and up to the leading edge? Where would I stop on the leading edge? How close to the trailing edge should I go? Does this picture illustrate the area you are talking about?
Attachment 12123

I understand that color matching will be a challenge but ... they have a white that is very close to this that I can live with.