A method for forming a plurality of adhesive fastener assemblies includes the step of providing a substantially continuous web of substrate material along a selected, longitudinal machine-direction (132). The substrate web has a laterally extending cross direction (134) which is substantially perpendicular to the machine direction, and has laterally opposed, longitudinally extending side edge regions (142 and 144) thereof. A selected fastening means, such as a layer of primary adhesive (54), is positioned and applied onto a major facing surface (186) of the substrate web (140). A first longitudinally extending web of stiffening material (154) is attached to the major surface of the substrate web (140) at a location which is proximate a first side edge region (142) of the substrate web. A second longitudinally extending web of stiffening material (156) is attached to the major surface of the substrate web (140) at a location which is proximate the second side edge region (144) of the substrate web (140). The web of substrate material and the webs of stiffening material thereby form a substrate composite (192). The substrate web is separated along a longitudinally extending medial region thereof, with a substantially regularly undulating serpentine separation line (158) to provide an opposed pair of fastener tab subassemblies (194 and 196).