The plastruder's done, so I set it up and gave it a try.
Good news: I actually got my first plastic out of the nozzle!
Bad news: at some point, the plastic clogged up and pushed the heater barrel right out of the PTFE plastic.
I'm waiting for things to cool down enough so I can figure out what happened. My guess is that I had the feed speed too high, or maybe the plastic was melting too high up, or maybe the plastic rod kinked.
This oughta be a fun repair...