If you provide hair and makeup for your attendants, then hire additional artists for them to be taken care of separately. One artist should only being doing a maximum of 5 people. A more economical option is to book them appointments at a salon or store and have them put their dresses on with you. If you leave the beauty routine in their own hands, then consider hiring your makeup artist to stay an extra hour to do touch ups on the already made-up wedding party.