I've seen a lot of answers referring to track widths but nothing that concentrates on copper planes.
I'm designing a 300mm by 300mm PCB that's 1.6mm thick and using 2oz copper weight. Evenly distributed around the board are 110 APA102 RGB LEDs (similar to WS2812B). Their max current draw is around 60mA. So hypothetically with them all on max the current draw is 6.6A @ 5V.
How can I calculate whether the PCB can handle this, and what the temperature rise will be?