Itinerary:
EVA Air
SFO-TPE-CAN arrive Oct 12th

Cathay Dragon
CAN-HKG-TPE depart Oct 15th

Will I have any issue for a 72 hour visa at CAN? I plan on visiting my grandma and won't have a hotel confirmation to show them. It follows the rules and all but just wondering if a) since they're separate tickets, all I'll have to prove of my onward flight to Hong Kong is a print out of a flight confirmation and b) not sure if they're going to hassle me since TPE and HKG are all "part of" China even though they're international flights. Thanks!

Edit:
Also, is the "time measured from 00:01 the day after you arrive" for the validity of the visa an official rule??