Wow! What a tour de force camlobe! The single mindedness of the young is indeed a wondrous thing, which I'm sure that many here recall. I can certainly relate to your determination, to the extent that having been told by Daedalus House, "Thanks, but no thanks, but do try again next year", I did and then managed to get accepted.
In my case of course it was the reverse of yours, for I wanted to be a pilot and only a pilot. I had rehearsed my reaction if offered Navigator instead, and decided to call their bluff (if bluff it be) and politely decline. As it happened it didn't arise, but again that single mindedness is apparent...or was it simply bloody mindedness?
Smuj, the engs will know best of course, but was the relative structural weakness in the 40's that you mention a reflection of the power/weight ratio? Was the development of the jet engine the means of increasing the first so that more structure could be added to the second? Even the late WW2 fighters seemed to be more rugged than the earlier ones, especially the ones with large radial engines. Merely an impression, and I bow as ever to the experts...