I think the most accurate way woudl be to use all permutations because you must consider the possible times when the dealer consumes a queen of hearts in the blackjack greatly altering the probibility of the event.
WOO lists 135360 permutations out of a total 9294695280 possible for a rate of 0.000015 a very similar number.
This event is relevant to the lucky ladies side bet for blackjack tables.
While the event is incredibly unlikely in contrast to the payout for the event, the hosue advantage is not as high as it suggests because of the other payouts. For example, you may be dealt two queens of hearts only to find the dealer does not get a bj, in this event you still get payed typically 125:1
The bet is beatable with card counting methods revolving mostly around the queen of hearts, but it also beatabel to a lesser degree of efficiency with conventional card counting systems designed for attacking the based game of blackjack.
The bet is very profitable when attacked because the effect fo removal per point count grows exponentially offering very large player advantages in the very few hands offred at a player advantage.
The house advantage for the side bet is greatly reduced with MORE decks in play, unlike blackjack itself, which, **IN GENERAL** is the opposite.
When attackign this bet, hands at player advanatge are very rare, and represent less than 0.5% of all hands whitnessed. As i said, thoguh, the player advantage grows fast and hands at +110% average ROI are normal.