Nothing beats genuine research, and someone like me has a distinct advantage over most in other countries (especially the size of the U.S.,) since I'm only a 45 minute drive from the U.K. National Archives, in London. It's something of an eye-opener to see how often official paperwork contradicts long-held beliefs, or can, at times, confirm them. We have a blanket ban on any files being opened for, at least, 25 years, which means that nobody has seen many of them until the late 1970s (a few, obviously very sensitive, files are closed for 150 years.)
As an example of what can be found, there have, on here, been some very deprecating remarks about the continuation of the Hurricane production long after its usefulness, as a fighter, was over. The files show that it was never envisaged as a fighter, after April, 1941, and was to be used only for ground attack, hence the bomb, rocket, and 40mm cannon variants. This all came about because the Typhoon was delayed by engine troubles, and the Whirlwind couldn't do all of the tasks that the Hurricane managed (try hanging 2 x 40mm cannon on a small twin-engined fighter.)