Oh I guess I never posted a resolution. I didn't have time to deal with the radiator immediately since it was the end of the fall semester and I still needed to use the bike since my backup bike still needs repairs
I just added water to the radiator before every ride. Some of it still boiled out but no overheating issues. Did that for several weeks. Eventually I noticed that fluid stopped boiling out and I didn't need to add water anymore. Huh ok. Went back to do another cooling system flush and found some thick grey goop sitting at the bottom of the coolant overflow tank that was preventing anything from going out the overflow tube. Looks like I boiled out whatever was clogging the radiator. Cleaned up the goop, refilled system with Engine Ice, and had no issues since. My problem ended working itself out. Go figure.