Convenience-feature sheet metal end closure structure and tooling apparatus including a new scoring tool configuration (94) which enables a peripheral scoreline (102), which defines a separable convenience-feature endwall panel (112), to be located contiguous to the end closure chuck wall (100) which interfits about its periphery with the open end of a container side wall. The resulting convenience-feature endwall panel is separated such that substantially no obstruction to removal of solid-pack contents as a single piece remains. The separable panel (112) can be formed with a multiple-layer fold (127) of sheet metal extending along its periphery so as to shield torn residual metal remaining with the panel after severance along such peripheral scoreline. An elongated, longitudinally-rigid integral opener (148) is placed at a selected designated location on non-circular configuration endwall panels which, in cooperation with novel shaping of chuck wall tooling (170), enables desired chuck wall support, free of registry concerns, during chime seam assembly of the end closure with a container body of matching non-cylindrical configuration.