I’m having trouble wrapping a rail i modeled around a helmet. But shrinkwrap deforms and almost flattens the mesh. I also tried editing it in edit mode and grabbing it in sculpt mode, but that just made the whole thing look messy.
I think what @oo_1942 means (I didn’t watch the video) is to duplicate the faces from the helmet where that part is located at and model those into the part you want.
Looking at the pics you provided, if it was me, I would duplicate the inside edges/faces of the part that should touch the helmet, and separate them out to a new part (P-key). Now from the side view with the new part in edit mode, set blender to snap to surface, and hit the G-key and enter. That should snap the new part to the surface of the helmet.
Now with the original part, I would use a lattice on it to get the outside curved shape to the part, then join it to the new part, and fill in faces where where needed.
If you need more detailed instructions, lemme know…
There is also this trick to “bind” the wanted properly subdivided geometry to a subdivided plane and then shringkwrap that plane to the wanted surface… so the bounds object gets properly bend…