TL;DR:

I shared my experience guest-lecturing at Harvard. I talked about how the professor had a surprise challenge question, and that the app failed to answer correctly in front of the students.

I then talked about why it failed, some of my attempts at improving it, and finally how I succeeded. I then talked about how the final solution is significantly better, and that the model is now more than capable of generating these complex rebalancing strategies without any issues at all, even for a list of 100+ stocks.