Sky Venture, well it didn't look long at all.
I want to say a few minutes, maybe 10-15 at the most, but check that.. We were watching from the observation deck.
Its hard to say really. My DH who was a skydiver, said it seems a lot longer than what it really is.
there were some teenagers getting ready for the orientation/prep when we were there. They got there an hour early, for "training/suiting up/video, etc"
They may include that time as part of the package... so maybe your time in the tunnel is short, but they count training, etc. in that time..