How do different sizes of panels affect my system? Is a larger panel better?

Panel sizes don’t affect the outcome. A 3.6kWh system is what it says - a 3600W system which can be made up of panels of any size. However in urban areas where roof space is at a premium, higher wattage panels like LG's 360 NeON R  panels, help you put panels that generate more power on your roof.