How to transfer information between two BPI M64s using GPIO?

I am new to BPI and I’m still learning. I installed 3.10.102 GNU/Linux on two Banana PIs. I want to use the GPIO to transfer files in the range of 100s of Megabytes from one of these two devices to the other. I am thinking of SPI or I2C (Obviously I’m open to any new ideas in this regard). Can someone provide me with some guidance in this regard? Is this project even feasible? Is there a link online for any sample Python code for SPI Protocol so I can use as a template and learn from?

Thanks and regards.