

Question about hot to get 30 more visa-free days
Hi and thanks in advance for the help!
I'm an Italian citizen, came to Shenzhen on December 24th as a tourist and originally planned to go back on Jan. 11, but since I enjoyed my stay I first changed my return flight to Jan. 22 which is when the 30 days would expire, right? Meanwhile, though, I made friends here, I seem to have found both a job at a language school and, even more important to me, a woman I've fallen in love with and who reciprocates my feelings. At the school they made me sign a 1-month part-time contract, saying that they will change that to a 1-year full-time contract after the CNY break. In the meanwhile, I'm supposed to make a "visa run" to HK and back so that I can get 30 more days visa-free - by then they should start the work visa process. My questions are:
1) do I need to go to HK precisely on the 30th day (so on the 22nd) or can I go earlier? How long must I stay there? Can I literally jump on the next ferry back to Shenzhen or do I need to spend a night?
2) when I arrived I filled the immigration form with the originally planned return date, which I then changed (I've always been in hotels so I think they've registered me with the police). No problem there, right?
3) If I understand it correctly, I will need to fill in a new immigration form as soon as I re-enter Mainland Chian, right? What am I supposed to write this time? Still that I'm here as a tourist? And what about the return date? My flight ticket will probably be lost (I don't know whether I can modify the date more than once). Do they need proof of an existing flight reservation? Or do I simply write down the 30th day of the "renewed" visa-free period as "return date"?
Sorry for the long message, and thanks again for the info you can provide!