re: 2 or 3 wires? the best option if you have to buy the wire new is to have the rectifier at the bottom of the tower in a suitable weatherproof box. then you can run 2 wires to your batteries. i have thought about having the batteries at the bottom of the tower as well,and then you can run normal mains wire to your house. the only trouble with that idea is you might forget to check your batteries,and if the inverter trips it will do it when it is wet and windy or snowing and of course dark.
cheers
bob golding