I just bought a 20" Aurora Firefly from a great seller on this forum, it's really a nice piece of kit!
One thing though, my 430EX doesn't seem tall enough to fit into the hole/entry for the softbox. If I unlock the head and tilt it upward, I can get it in, but then it's not shooting straight into the softbox, and the head is in an unlocked position so it will bounce around inside (if the box is being moved around)
This sort of shows what I'm talking about, I should have taken this at a different angle to show how low the 430EX head is. I do have the mount at it's highest position.