Good luck, man. It seems Z visa issuance in HK will be the key to the door in your case. I think that's still possible, but perhaps that will be discontinued fairly soon. I read somewhere else that HK would require a local med, and then probably you'd have to do another one back on the mainland. Another thing to bear in mind is the criminal background check.
No need to advise you what you need to do - you're an old hand China-wise. But even old China hands can end up in a jam through no fault of their own! Anyways, all the best!