Quote
Kickback is fine. Just because no italians or poles play it is irrelevant: why not argue that no NAs play what the italians play, so the italians should stop playing their methods?
My argument was only to show that "no kickback ever" is playable agreement as showed by elite players around the world. My arguments against kickback was that people, even great players, regularly have disasters because of it and if you have one -12 imp disaster because of kickback you will have to play 20 more years or so to make EV for it, not worth it.
If you have various bids in various sequences as ace ask with many not fully consistent rules guarding it you better be Meckwell to not screw it up.
Imo if you are not full time player having hours a day for working on your system you are hurting yourself by agreements like kickback because gains from it, if any are very small and disaster bound to happen very expensive.
As to the OP problem I don't understand how opener is bidding anything here. He is supposedly 18-19 balanced and partner might have 6hcp with 6-4 distribution, say: KQTx JTxxxx xx x or even weakier hand good enough for game opposite 18-19. If opener somehow feels his hand is good enough for forcing a slam here (which might only be because of miscounting points or something) the only reasonable slam might be in hearts as 3NT denied 4 spades. In that case 4NT must be rkcb for hearts as ace asking for spades is pointless in the context.