I've gotten everything back together, and I'm very pleased with the results. The large red thumbscrew fits perfectly and is the ideal length... and I actually think that the weathering job on my new emitter looks even better than the old one!

I've sawed down my blade a little bit but that seems to make it brighter and more even which is a bonus and I can safely swing it around in the house without hitting any ceilings. Not all bad!