A wall structure for either a building or a stand alone wall is formed with stacked horizontal elongated panels. In this regard, according to one example embodiment, a microball delivery assembly includes a mask with at least two microball holder to hold at least two different sizes of microball that may correspond with at least two different-sized openings on a substrate, to provide simultaneous delivery of different-sized microballs upon a substrate. The method, system, and device are applicable to a training procedure of a Vectored-DSL precoder or canceller, so as to rapidly exit the training procedure.