I've been playing around further with Bob and unfortunately I managed to get it to delete its own settings file!! So I think I'll pass on that one for now.
of course it is trivial to share if others want readonly, and if more than one editor coordinate edits.
I can vouch for bob being quite stable and the multi-user version of tiddlywiki. Occasional issues arrise but if you can keep it in a trusted network e.g. LAN or secure it on the internet It is the best solution.
I am keen on using single file tw-reciever on php and it has some overwrite protection but this only results in a failed save.
I have the pieces to introduce a serial editing mechanisium ie check in check out, but just getting over eye surgery. This would work on top of single file and node if played carefully.
If users need to customise a little but not publish changes you could use the local storage plugin. For safety export changes to a file as a backup should the browser reuse the space.
I have being playing with the idea of secondary editors saving or sending their edits as json file of tiddlers for the owner to review and import. This could work for surveys and more.
Regards
Tony