Not sure why the previous thread was locked. No warnings were given. Nothing. Oh well.
After much research (including reading older threads and watching YouTube videos) I just ordered the small-engine variety and will try it in my 1982 Yamaha 650 Maxim project bike.
It should arrive late next week. I'll put it in, put in a few hundred miles, and report back.
Hopefully I didn't just waste $50, but I've spent more than that in my younger years with nothing to show for it other than a pretty good hangover the next morning.