...the solution is to set the Include parameter to 'submission_history'. But I'm not sure exactly how to do that when interfacing using Python (and specifically the requests library). I try setting the params this way, with no luck.
That didn't work either. Obviously, when I call requests.get, I am setting params=params, and the change to the per_page parameter is working correctly. This is probably an issue with the syntax specific to the requests library, but I can't seem to find any info there. Hopefully someone here has wisdom for me 🙂