I called CS in Vancouver last night in regards to booking the transit hotel online. The agent replied that it's not necessary to book the hotel ahead of time, just go up to the transit counter on arrival.

When I emailed CS in Toronto, they only sent a vague reply to call their China hotline number...

I also have the dilemna of wanting a confirmed hotel confirmation to avoid denial of 24 hr TWOV stay permit. My flight lands at 730pm, and most hotels have cancellation of up to 4pm I believe.... So I don't know how to work around that.