Some advice that I would give to someone creating a wiki specifically for a class working synchronously:

1. Students must write their information in Word first – for better grammar, but especially for back-up.
2. Create separate designated pages for each student to work on – possibly name the pages with their name embedded to be changed out later – as the wiki creator, you may be the only one to have the page creation rights.
3. If you know multiple people will be working on the same pages at the same times, allocate time buffer zones that people may post – for example, if 4 people work on the same page, one may post between 4-6pm, another between 7-9pm, another between 10-12pm, and another between 6-8am.

There are always Revision histories, but having 15-30 students post on the same page at the same time DOES NOT WORK. Separate the tasks and times as best as you can.

I would actually recommend Google Docs or Microsoft One-note if you are networked and have that option.  It depends on your final goal of the project.