I was a bit worried it would be slow with 20 people, but it didn't feel that way to me.
For separate groups, although that is a problem, one benefit of the ranking system is that you can mitigate this quite a bit, by splitting people up, which I think is usually done. Does this not work well enough for you? It's never super accurate, but reduces the problem a lot, and any tournament that big normally has a knockout of more than 8 people, meaning it's pretty likely the 8 best get through.
I will be at Durham so look forward to it :)
by Brook Roberts, in response to this post 2015-09-29 09:53:13