1 panel 2, 3, or 4 panels?
As you will see here from comments and suggestions from learned people on this board bigger is better bumping your run to 8ga will drop your losses alot.
Home depot has 3/8 cable it has 3 8ga insulated wires with a solid copper ground 4 conductors total. 125' was under $100 in Cali. I used this on my array and got another 16 watts down. With a run of only 8 feet from disconnect to panels. I had 12ga on it prior with a little extra at the end As you will see on this board. Keep your wire runs as short as possible. Wire resistance adds up to watts lost.
And when you have a setup like yours and mine (4 x 55 watt panels) every little bit of loss equates to that much less you can get out of the small array.
You could use the solid copper ground as a leg if you wish it will carry power.
A MPPT controller would help as well because of the loss from 17-21volt open circuit to the closed circuit if you have a controller like mine or direct battery connection. (not recommended) .
If you do not plan on increasing the size of your array this will do and it is much cheaper than the Outback.
BZ MPPT-250: 12/24 Volt, 250 Watt MPPT Charge Controller
Only $99
they have them here www.discountpv.com/chargecontrollers/
I love the feedback that i can get from the people that use this board. But not everyone has the same needs or ability to add more panels. If you can only mount 200 watts of panels then you need to get them as efficient as possible.
Sure another 80 watt panel will offset the wire loss and it's cheaper than an outback.
But i have one coming and will then rewire the panels for 48vdc use instead and drop my amps output down 1/4 with a corrosponding drop in wire loss over the same distance/ga of wire. But still run my battery bank at 12vdc.
www.thesolar.biz has the outback mx-60 shipped for around $500
watts is watts i prefer putting them into my batteries and not using them prior. As heat in wire going from the panels to the charging station.
And since eventually (once i move) i do plan on increasing my array hence the outback is the best choice for both short term (since i can not increase the current size of the solar panel array) and long term Once i am able to get more panels in use.