At MP I would pass, at IMPS I am torn between 4♥/5♣. Partner would X with any hand with shortness and a 4-3♥ fit would not play well with this poor trumps. Of course it depends who are my opponents, if they are known to be particularly aggressive I may choose to pass even at IMPs.
Responder may have a hand with 5 hearts and club tolerance too weak for a GF 3♥ bid Qx KJxxx x Kxxxx. Of course this is not the most likely hand that responder can have but its not impossible.
I think I would bid 1/4♦. Against very good players I would tend to bid 4 to give them a tough problem, while against weaker players I would just bid my hand and let my partner make an informed decision.
Opening aceless 11 count with 2 jacks and 4-3-3-3 vulnerable is really poor in my opinion. I would open the hand only if we agreed to open all eleven counts. Furthermore as others mentioned it is better to pass 1♠ and not bid 1N. Bidding 1N shows an exceptional stopper (AJx(x) is a minimum requirement) IMO or a maximum hand with an ordinary stopper (Kxx or better). If very agressive openings were agreed I could give 30% to South for bidding 3♥, but still think 1N is far worse than 3♥
I think X is really poor with a 9 count, especially when you have half your points in their suit. As East, I would start with 2♣ to show a strong hand, opposite as little as Axxx KJ10x xxx xx game is on a finess.
Pass in tempo. 5♦ is wide ranging and there is a good chance they don't bid the slam if you pass. If they bid 6♦ in confidence you can still decide to sacrifice although I wouldn't do it at this vul.
North knows that South has 6 spades, so I think its pretty obvious to bid on. Opposite xxxxxx xx xxx xx slam is on spades 2-2. So anytime partner accepts we will play a good slam and i cant see how the 5 level can be too much. I personally put the 22-23 NT in multi so the auction would go something like: 2♣-2♥ //negative 2N-4♦ // 24+ balanced unlimited // texas 5♠-6♠ IMHO its not worth it to play split ranges, especially when you have 2♥ negative available. When opener has around 26+ he just makes another try opposite a positive response. Playing a strong club we will bid: 1♣-1♦ 1N-2♦ // either 5♦4M or 24+ bal forcing 1. 2N-4♦ 5♠-6♠
1. Partner may easily have something like Jxxx Axxxx x Kxx. Oposite that slam has little play. 2. 5♣ showed a slam try opposite some random 7-11 count. If we believe we can make a slam opposite as little as 2 aces, we need to have a pretty strong hand to justify the bid. 3. If the passed hand partner declined my slam try with working AAK , I think I will start looking for a new partner.