OK, with a Voc of 48.6V, you CAN NOT have three panels or more in series. At room temperature three panels in series is already ~146Voc, so it takes just a cool (not frosty) morning to bump the voltage above 150V. So, wire two panels in series. With six panels total that's three parallel strings of 2 panels each, written as 2S3P.
Those six panels are likely to put out (375W X 6 panels) / 50V charging = 45A theoretical. With 85% derating, you are likely to see ~38A max in the real-world. With a 60A limit, you could potentially expand to (60A X 50Vcharging)/85% = 3530W of panels with no overload concerns. If you want to add even more panel watts, orient some of the extra W Southeast, and some Southwest, which will flatten down your noon peak, but broaden out the overall daily power curve.
But, why the separate charge controller, when the inverter you want to buy, the SunGoldPower, already has a built-in MPPT that can handle 120A?