Lance 1181 solar install?

If you go with an MPPT controller, you can wire your panels in series for 24v to the controller (Actually will be about 34 volts), and the controller will drop it to the proper battery charging voltage without much loss. Higher voltage in the wire means less current, so thinner wire will work. EP Solar makes an MPPT controller that will take up to 100 volts in. You could have 4 panels in series and at 60 volts in, 300 watts would only need 5 amps - well within the capacity of 12 ga. wire.