Distributor recurve
The 9R governor has shorter slots, so that it allows a lower maximum mechanical advance. Its heavy spring also has a shorter loop on the end, to go with those shorter slots. For that reason I used the 79 springs along with the 79 governor and vacuum pod. I left all the other parts from the 74 distributor in place, as it was working well.
I answered my question about honing the governor shaft. A rolled-up piece of 400 grit sandpaper did the trick. I was actually able to grip the paper roll with a drill and slide the governor up and down while spinning the paper. That red 3M sandpaper is pretty good stuff.