They won't give cross/tailwind for a non-duty runway.
Ah, my mention of 20 in 30 mins wasn't related to your 20 per hour - probably where I got the number from but it wasn't a deliberate choice.
I entirely agree that's the point of COBT - presumably the wheels fall off when the "model" they've used to generate the delays doesn't match reality very well. As I mentioned earlier it's working after a fashion as the peaks aren't don't seem as intense. Mind you go back 15 years and holding was routine quite often two or three times a day.
Fair enough, although it seems that people are taking attempts to explain how things work from the ATC perspective as defending it.