Ok, so it looks like the API port is 4028.

My problem is that I can open up port 4028 for forwarding to only one device. Is there a way to do this for multiple miners or will I need to modify the python script to used different ports and then use port forwarding on the router to point back to 4028

eg port 20001 goes to the 1st miner on port 4028
port 20001 goes to the 2nd miner on port 4028