Preferably sooner rather than later!
I've only been given an approximation on the keyhole towers. Obviously everyone is excited however to see them thread the needle with the zero-g roll.
I'll shoot an email to see if there is a build schedule for the zero-g roll, as well as the dive loop by Blue Streak. I'm pretty sure all track has been produced and is on site. In which case, once the keyhole towers are up and footers are laid, they can build away.