Apologies for the delay in posting the solution.
The correct move is to shift the K of hearts in column 6 onto the empty column to expose a new card, and then clear the suit with the 3-2-A. The difference is if we expose the Three of hearts then we have two empty columns instead of one. Of course the odds are small since there is only one Heart Three unseen, but nothing to be lost by trying!
Note that if you were scoring according to number of moves instead of playing a “pure game” (i.e. just winning) then you would probably not procrastinate and save a move. Since the game is going so well, you would probably expect to win anyway.
Oh, in other news I have just lent Steve N Brown’s book to my work colleague so I expect to see some big improvement in her play in January 2020. Bring it on!