I just pulled the carbs, took the bowl off 3 and 4, compared the floats. I did in fact have the float upside down... I flipped it right side up, put the carbs back on, turned it on, and cylinder 3 is now firing.
Sorry for the lower quality video... Last one was in the day time, and it was my roommate's Samsung edge. This video is right at dusk and is from my low budget Windows phone.
Still, much MUCH better... she's idling and throttling like I'm used to now.