The "tinny" sound comes from the 1960's technology baffles you are using. To soften the sound, you need to deaden the shape of the sound. You need something that is wrapped with a sound deadening material, like fiberglass, or is acoustically chambered. You can experiment with the ones you already have by wrapping some exhaust fiberglass loosely)around the baffle, then aluminum heat tape around that, and lacing it all in with some stainless wire. Should take the edge off your e-note.
