Firstly, via SPs.
2H is easy to forget. A common error is to respond 1S = hearts, then soon realise that you can’t show this shape any more, then do some creative sorting. (1-5-4-3?)
4D is good news, then no CQ is even better, don’t need that. 9SPs and none in clubs must be 3 SPs in each of the other suits. Therefore SA and H-KQ.
5H confirmed the stiff spade honour. Some methods ignore singletons and that would be useful here. Note that stiff kings count as 1 SP. It might be good to be able to show that, rather than partner think you have an extra queen elsewhere.
A problem for our methods is a suit with 3SPs in which the asker has no honour. Diamonds is key suit for the grand because East would make exactly the same bids with D-KQxx. Now 6NT will make opposite that, hence the final 5S ask.
East would bid 5NT over 5S to deny a second heart honour. Therefore Axxx.
6C say “I have a second heart honour but no second diamond honour.” Perfect.
It can be difficult to sort that out in time. West might take the view that the CQ is irrelevant, so ask for kontrols, hoping to pick up some red queens on the second pass.
That produces
This works just as well.
West finds out about the important kontrols, then goes back to the start to check for the HQ. Note that D-AKQ and no heart card would be just as good but awkward to nail down via kontrol asks. This is because there are two 0/2 suits.
