The procedure in a preliminary hearing is only designed to determine if there is sufficient evidence to either bind the defendant over for trial or to hold for a grand jury. There are other purpoes for the P.H. but basically the justice is not interested in guilt v. non guilt--only whether based solely on the prosecution's evidence there is probable cause to believe that a crime was committed and that the defendant committed it. Some justices would not permit much cross-examination although Bonaventure allowed Df's attorney great lattitude. I am not familiar with Nevada procedure and that may be more lenient than that followed federally or in my state.
One other thought: the P.H. can serve as a discovery device for a defense attorney; there is only limited discovery in criminal cases and it appears to me that O.J.'s attorneys made the most of the P.H. from that standpoint.