Will RYK be as good a player as Kasparov? Of course not. Sometimes the RYK system will randomly make dreadful moves which the real-life Kasparov would never make - start the game with P-KN4. I assign such moves a low probability, but sometimes the computer makes them anyway, by sheer random chance.

Don't think this is right. RYK would not make dreadful moves that you would not think Kasparov would make under any circumstances, unless you were assigning odds too high to those moves. So unless you think there's a chance that Kasparov would make that move more often than you would, you would assign a log-odd of -200 dB or something, effective 0 chance.