First, positive and negative are just relative to what is known as the Standard Hydrogen Electrode. Positive reduction potential just means that it is more likely to happen (the reduction) than H+ being reduced to H2. Negative reduction potential means that it is less likely to happen than H+ being reduced to H2. Alternatively, the reverse (oxidation) is more likely to happen than H2 being oxidized to H+.
I am not entirely sure what you are asking, but I hope that cleared up some confusions.