In reading these comments, and those in the thread immediately above, I wonder if perhaps N should not simply have discouraged ♥ on his first discard? Perhaps that is risky lest declarer hold a 1=4=1=7 pattern.
I don't know. Discouraging ♥ so that declarer will know ...
The 8-1 number assumes RHO, holding KQ, will take with the K or Q with equal probability. That is a very reasonable assumption, almost a certainty, although if, with KQ, he will always win the Q (or always with the K) the odds are lower, though still lopsided.
I am sure that David is well aware that inexperienced players, holding the canonical QJ doubleton, universally play the Q. I believe that strong players have a bias to playing the J from this holding. I cannot prove the latter assertion; I wonder if anyone else believes it?