A method of manufacturing a magnetic read-write head, including the steps of presenting a row bar to a processing location, the row bar including an air bearing surface, at least one read-write head, at least one electronic lapping guide, and at least one trigger device, wherein each electronic lapping guide is positioned at a different distance from the air bearing surface than each trigger device, and wherein the read-write head and at least one of the trigger devices include a multi-layer stack of materials; lapping the air bearing surface while measuring the electrical resistance of at least one electronic lapping guide and at least one trigger device until the resistance measurement of the trigger device provides an open circuit reading, and measuring an offset resistance value of the at least one electronic lapping guide concurrently with the measurement of the open circuit reading by the trigger device.