Hi rsq, carry on doing as Chip (spokes) says and you'll get there in the end.
Don't worry about the CB92 spark advancer, all the Benly series twins from 58 through to 65 had the same advancer. I'm not sure where I got it from or where it is now but I had an advancer that I took off a motor marked C90, the very first 125cc twin, there was no difference at all.
Sam.
