Well, I played to not assume four diamonds in South's hand. Still think simple attempt to cash out is correct. Not a hand for generalisations about ducking lead to KJxx.. Amazed that no 'good' players would consider this.
Claim stands. At the lower levels they say don't claim. Not bid advice - more especially if you are so clever as to claim one down. You must have a very tolerant partner.
I don't think many ACBL players play against multi 2D. You want actually to play in 2S with the North hand? That's your value bid over a possible weak hand. Not for me.
I think you need to know the players methods if you want to get into this in depth. It seems people assume North has shown a solid 7-carder with good outside controls. Four spades wouldn't be my choice on such a hand - but I don't know about this partnership.
You may not have noticed that in my old fashioned auction North bid RKCB, and he knew he had a singleton spade ace. I did look on with interest at the scientific autions where this minor point is missing.
1♥ (5-card suit) 3♦ (Game force/slam invitational, heart support or long solid diamond suit) 4NT (RKCB for diamonds) 5♣ (0 or 3) 5♦ (relay to show queen of diamonds or pass) ... whatever 7♦ We could do it in the old days.
I'd bid 3♥ at both forms of scoring. At MPs it seems automatic since rare very large scores plus or minus are irrelevant. At teams frequency is replaced by what they are doing in the other room. Well, I think they are bidding 3♥ just the same as me.
4♠ Obvious answer is that I have a good hand with lots of spades. Only real downside (other than -1 versus +300) is that partner with some spades and singleton heart will be under pressure to go one more over five hearts.
If you just play the percentages, nothing clever, noone can really do better. Even Michael Rosenberg, without the Jack, won't be able to fool you - and you won't be embarassed when you futilely try to catch him out.
When I go for 500 I gain one imp. When I go for 800 I lose five imps. It makes no sense, but hard to resist in when you're playing for points. Just depends whether you think you disturb the opponents more than partner.
I'm OK with the bidding, and will bid 2S now. I've got a decent opener. Why can't partner have a penalty of 2C? Now I can't see that I must play in a 42 heart fit rather than a better spaded or diamond fit.
If you mean after double ... 1H, then over 3C I'd double again. I understand the advantages of getting a 5-card major into the auction, I'm not convinced it's usually going to help much when i've got such a big hand. I like the generalisation that I overcall when I can (NT or suit) up to about seventeen points, and double when I am too strong.