Qavion. Thanks for going to all that trouble. Having looked closely at the Non-Normal QRH on flaps up landings, I am beginning to think that LEM is right and that where the word low idle is used (in associated paragraphs on flapless landings), it probably means that lower than usual approach power is needed to lack of drag. Not to be confused (well, I certainly was) with an engine condition known as high idle and low idle.
I still don't know why in a flapless that the Flap 5 maneouvering speed is set on a bug.