So, a few questions remaining.
Do we know anything at all about how long WTC7 took to collapse? If not, why not, why do Truthers say we do, what is wrong with their analysis? (Well, the two or three most common Truther analyses then).
To my knowledge, the best timeline about WTC 7's collapse is still contained in the
Progress Report on WTC 7 released some years ago by NIST, on Page 26. It does not contain an estimate of the final collapse duration.
Gregory Urich postulated that the collapse time of the final stage was approximately 6.5 seconds in length. I do not know where this number comes from, presumably from the various videos of the event. I think it's pretty close but no better than +/- 1 second in accuracy. See also the discussion in
this thread.
Why we don't have a better estimate is that it really isn't important. The whole meme about collapse time proving or disproving a particular failure event is and always has been ridiculous. In order to materially speed up or slow down the collapse, damage done by nefarious means (explosives, beam weapons, thermite nano-buggery, whatever) has to be comprehensive and vast -- read "impossible to conceal." Otherwise, damage done through such means falls well within the bounds of uncertainty regarding structural condition.
NIST may release a more precise estimate of the final collapse time in its upcoming report. Or it may not. There are many things I'm waiting for in the report, but this is not one of them. It's a dead issue. I should note, however, that Dr. Bazant and Dr. Greening are two who disagree and think this issue
is important, but theirs is a minority opinion; I invite you to follow up with them to get a feel for the potential significance.
How do we know what caused the structural damage to WTC7?
What is the story with the Barry Jennings/dead body thing?
One imagines that, had there been a different source of structural damage, it would have showed up on video... There's little question that the collapse of WTC 1 in particular caused extensive damage. Note, however, that
in my opinion WTC 7's collapse was ultimately due to fire rather than structural damage, with the damage merely serving to accelerate and spread the fires. NIST may prove me wrong, of course, this is just my considered opinion.
As far as Barry Jennings goes, he clarified himself to the BBC in their recent examination of WTC 7. Some in the Truth Movement reject his comments therein for their own reasons, none of which I find compelling. You be the judge.
Hope that helps a little bit more than just telling you to wait for NIST to finish, anyway.