I dont know of any emperical science proving more metal equates to better tone or resonance as it relates to electric basses, personally I think its more about the electronics.... but I digress, I would buy a bridge based on what it can do such as quick release strings , or the quality of the saddle and movement of said saddle. Leo Fenders bridges were pretty basic but they worked just fine, today you have a lot of refinements which are nice , but do they make it a better "sounding" bridge if they have more mass, I dont know, you couldnt prove it by me.