Having finally got to the end of the thread, another bit of data of dubious relevance.
I was part of the crew of one of the recovery helicopters at Lockerbie. The debris trail was 70 miles long, and notwithstanding that we knew where to start, bits were obvious all along it. I'm fairly sure that even crossing it at right angles, we would have picked it up in about one leg in three of a creeping line search. I've done a lot of searches over water, and looking for sunken ships that were actually sunk more-or-less where someone thought did tend to reveal debris fairly quickly.
So, if the search is anywhere near the right place, I would expect an in-flight disintegration at altitude to lead to discovery of wreckage / debris in fairly short order.