I went to the box office in 2007 at about 3pm to see if I could get my dad a last minute ticket and they hadn't got any left at all. We were also keeping our eyes peeled for touts but never saw one - presumably keeping a low profile due to the heavier policing of the event. Can't imagine there were many (if any) still to be had on the day tbh.

With respect to the upcoming residency, I'd be willing to bet you'd easily get a ticket even if you turned up 5mins before doors.