All good points, and as you say there's little
on the record that supports my take on why the two post trinity bombs were
always going to be used.
Circling back to at the time, there are copious notes on materials, orders, deployments, and boxes of documentation, and then there is relatively little on the underlying thought given to whether the two bombs should even be used at all. At the time. No shortage of after the fact recollections of course.
While I'm not a historian, more an applied geophysics dabbler, I'm familiar with the material, I've met and talked with Alex Wellerstein, I once interviewed Mark Oliphant, and I've spoken with a number of the technical people who came out for the Emu Fields and Montebello tests.
In the context of an ongoing bombing campaign and truly vast amounts money and resources spent on creating new weapons it's difficult to imagine a scenario in which the bombs would not have been field tested. If that kind of take is a foundation then everthing written becomes bookkeeping and for the record.
In life, where there's momentum politics will often follow rather than lead.
Regardless, I simply have an opinion (well, many and not all consistent with each other) and not a book or a career; I principally enjoy jolting people who have a particular fixed view of many events in history to become aware of wider fields of opinion and to consider how consensus views evolve over time.