When a difficult shape is giving me troubles, what I usually do is take that one I already have, imperfect as it is, and just draw over it with shrinkwrap or kind of retopology vertex by vertex. because now I have a base from where I can jump start from and I can basically draw good topology over it. Use snapping over the surface to retopo and now I don’t have to worry about shape and form, just focus good on perfect topology and solve the puzzle.
