And I won't argue with it. Thanks for the reference. I was relying on my memory of Rhodes' book -- which also comes highly recommended. Very readable and, in a virtuoso performance, somehow makes the physics involved quite understandable to the layman.
At any rate, there was no bomb "back in Utah", as Tibbets thought. Not in early August. Tibbets may have believed there was, but LeMay would've known better.