Three thin, concentric conducting spherical shells have radii \(R\), \(2R\), and \(3R\), as shown in the diagram. Initially, the innermost shell (radius \(R\)) has net charge \(q_1 = 0\), the middle shell (radius \(2R\)) has net charge \(q_2 = +4Q\), and the outermost shell (radius \(3R\)) has net charge \(q_3 = +Q\). A thin wire with an open switch connects the innermost shell to the outermost shell, passing through a small insulated hole in the middle shell without touching it. The switch is now closed. After electrostatic equilibrium is re-established, what is the final net charge \(q_1'\) on the innermost shell?