Getting back to your original question, I do not believe that it is possible to wire the Lopolight to power your tricolor, XOR your anchorlight with only the two wires leading up the mast. One of the Lopolight wires is a dedicated negative, shared by both lights, and the other two are used to power select either the tricolor, or the anchor light.
Using a set of diodes, and a DPST switch, you can reverse the polarity going to a fixture with two bulbs, but this requires using the negative lead for one circuit as the positive lead for the other. I don't see how you can do this with the three wire Lopolight setup.
Thanks very much for the specific info; that's just what I was wondering about. If the negative leads are connected and sealed together such that I couldn't get a diode in place for each individual circuit, then "that's that."