Ironically, accepting an F visa from a crappy establishment is, in my view, better than committing yourself into a legal work permit that could legally go against you should you object to your employer's nonesense there. There are scores of ridiculous employers on mainland China, aren't there?
By the way, HK seems to provide F only as of recent and for your Z you most likely have to get back to your homeland these days. If your employer does not pay for the trip, you might as well favor the F. :)

Cheers and beers to our views on topic