"also, i didn't quite understand this: "If you come on a tourist visa then apply for a working visa. If approved then you don't have to leave and come back in again."
This means if you are in Hong Kong and you have a tourist visa, then you apply for an employment visa. Once it is approved you do not have to go out of Hong Kong and come back in again you can just stay in Hong Kong.
Takes around 4-6 weeks on average but can vary on a case by case basis.
Sorry, but you would have to initiate the case with our company for us to go into detail about the documents that you require and the details of the documentation required.
If you want to talk further you can always send me a PM
