Originally Posted by
dh01
Moondog, your information is not correct.
"Visitors are not allowed to leave the transit city to other cities during the 72 hours. They can only depart from the same airport where they get their permit issued."
This is from the Chinese Embassy regarding transit without visa. The TWOV is valid for specific cities, and those cities only.
The OP doesn't need 72 hours. His plan is completely (as in 100%) viable since his total stay in China <24 hours. We've had many, many threads on this.
ETA: It's also worth noting that
TWOV applies at every airport in China that has international flights, but only a handful of cities have the 72 hour exception.