1. A method for delivering sub-perception modulation to targeted neural tissue using electrodes in one or more electrode arrays, the method comprising: receiving a user-provided selection of a desired active electrode list that identifies active electrodes for use to deliver the sub-perception modulation to the targeted neural tissue, the targeted neural tissue including dorsal horn tissue or dorsal root tissue, wherein the desired active electrode list is less than all of the electrodes within the one or more electrode arrays; and delivering the sub-perception modulation to the targeted neural tissue using the electrodes identified in the desired active electrode list and using a modulation parameter set to promote uniformity of a sub-perception modulation field within the targeted neural tissue, wherein the delivered sub-perception modulation using the desired active electrode list is therapeutically effective to relieve pain and uses less power than would be used to deliver sub-perception modulation using all of the electrodes within the one or more electrode arrays.