A lead assembly for an electrical stimulation system includes a lead scaffold that defines first, second, and third channels defined along the first major surface of the lead scaffold. The first, second, and third channels are parallel to one another and to a longitudinal length of the lead scaffold. A tapered guide feature is coupled to one end of the lead scaffold. The lead assembly also includes first and second leads with electrodes at distal ends of the leads, terminals at proximal ends of the leads, and conductive wires coupling the electrodes to the terminals. The first lead is insertable into the first channel and the second lead is insertable into the second channel.