Posted 2023-March-07, 09:55
I'm not sure I would be able to do that. My auction would go
2NT - 4♠ (SI with long diamonds);
5♣ (positive with good controls) - 5♠ (extras, spade control, denies a heart control);
5NT (positive. Without a heart control opener can realise that, say, ♠-, ♥QJ(x), ♦AQJxxx(x), ♣Qxx(x) or so is not worth another positive (which is the best hand responder can have with spade shortage), so the spade control is near certain to be the king, making the spade suit a source of tricks) - 6♣ (last train);
?
At this point opener can picture the spade king, diamond AQxxxx and some undisclosed extras, which is likely based on an outside queen. My agreements don't extend beyond this - 6♥ asks responder to bid 7NT with the queen of hearts and 7♦ without it, 6♦, 6NT and 7♦ are to play but 6♠ and 7♣ don't have an assigned meaning. Maybe one of these should ask responder for ♣Qxx (rather than, say, Qx or xx or xxx). At the table I would bid either 7♣ or 7♦, too afraid that 6♠ might be interpreted as a queen ask in that suit.
It is completely unclear to me why 7♣ in mw64ahw's auction has to be based on ♣Qxx(x), and what the systemic bid is with ♣Qx, or why shortage in the club suit is not permitted. I'm also happy not to play the 3♠ tool that way - the choice of game hands with both minors and shortage in a major suit are quite common, as are hands with length in both minors that might be worth a slam try only opposite a good fit.