You are right on now with TABLE_REFRESH and TABLE_CHECK.
As for when it will run. As I mentioned, the device tracks the last update date for the table and compares it to the interval (weekly for your example). On each transmit it checks to see if it has passed the interval and if so it will execute the check. Otherwise it will be skipped for that transmit. So there is no way to set a time for it since it will depend on when the user next transmits. It could be almost exactly one week or it could be 10 days if the user hasn't transmitted in a while for whatever reason.
--Bill