Some of those a dollar a watt panels are expensive to get shipped.
Oh, and charge controllers, inverters, grid tie inverters also have equal idiosyncrasies in efficiency. For example the 1200 watt units are just 4 300 watt units in parallel. The 300 watt models are most efficient at about 150 watts.
Many of the devices with mppt is not able to track multiple panels, so your best bet is a 1 to 1 ratio or string the panels for a high voltage and get a matching high voltage inverter. If you string panels, make sure those are not shaded or the inverter will drop out. One cracked or weak cell in a panel can cripple or limit the over all output of the whole panel or array.