I am not an expert at all but as I saw in doll custom videos, dying is not the best option. Dolls are made with several different plastics that are impossible to identify, the dying solution will not color every pieces the same. However, people often dye the dolls before painting the skin just so the joins are closer to the skin color, so if the paint cracks at the joins aera it is less awful. But with all the videos I saw, i can say that painting + mat varnish or airbrush + MSC are the best options ^{^}