Transit visa or visa-free transit

We are flying Amsterdam-Guangzhou-Hanoi. Would only have a 3hr stopover at Guangzhou airport, but the flight schedule changed and we have a 16-hour stopover now. (on the way back, we have a 9hr stopover). They are offering us a hotelroom, but this is outside the airport and we have to sort out the visa ourselves.

I checked...but it's still not clear to me. One says this, another says that.
It looks like we need to arrange a double entry before we travel (E 88 per person)!

Do we really need to arrange this before travelling (will be a lot of work) or is there another option? Such as arriving at Guangzhou, going through immigration (show the hotelinformation) and ask for a visa-free transit?

Anyone who knows this for sure or who has travelled like this lately? HELP :-(