Re: the closed concourse, I would say I generally prefer an open concourse during a sporting event, but I think it matters less when it comes to an arena that will mostly be used for hockey and concerts. Obviously open concourses are superior for baseball and football stadiums, because there are lots of long stoppages, so there's a need to get up to use the concessions/washrooms, but most people get out of their seats between periods for hockey games, and I think some of the benefits of a closed concourse (better sightlines/proximity for the lower upper bowl, better acoustics and atmosphere, better conditions for concerts/comedy shows) outweigh the benefits of the open concourse in Calgary's use case. Thinking beyond hockey games, I've been to concerts at arenas with open concourses and they had to draw curtains across the entirety of the concourse, to varying effectiveness.