Excellent find. You're very lucky to have a complete wonder wheel set up, very often the rods are missing and it's useless without them.
You should join the vintage Necchi Yahoo group.
https://groups.yahoo.com/neo/groups/...chineclub/info
The files and messages will answer all your questions. There is a great file on cleaning/unfreezing machines. Necchis have such tight tolerances that it doesn't take much to freeze one up. I use the basic principles to clean all my vintage machines.
Cari