Reasonable Grand Slam?

This is an interesting hand. My simple idea was that with no special distribution 7NT would make if 7♦ make. It's not exactly true as you see. We have 12 tricks, and the 13th comes in from trumping a diamond in the hand with the shorter trumps. Or, if you want to think in losers, you can say that one diamond is ruffed and another one on the spades. 

But how are the chances to make 7NT. If you guess the correct finesse in the majors, you have your trick. It does not matter if both finesses work. If both finesses fail, you can do nothing to make the contract. 

It gets interesting if both queens are on the same side. You can then reduce to 5 cards in the majors. Then one of the queens must drop. The same happens if one of them is a doubleton, of course. This line of play has the biggest probability to succeed.

The problem is to combine the two options. You can carefully observe the discards, and start by cashing the ♥A. If both opponents discard carefully, it will be pure guesswork. On my table, the ♥Q dropped.