FrancesHinden, on 2013-September-22, 15:14, said:
The pass of 3C looks a little odd with 5-card support, but it's actually not obvious what game you are making
If LHO has AQxxxx in hearts - quite likely on the auction - and partner has 1 or 2 hearts - also very likely on the auction, then to make 3NT you need one or both of (i) to be able to take 9 tricks on a heart lead without letting RHO in, (ii) to be able to staunch the diamond suit. They won't always lead the right red suit, agreed, but it would be hard to argue with, say,
AJ10xx x Kx AQxxx
when 3NT is very close to hopeless
Even if you have 5 spade tricks you are are unlkely to be better than the club finesse. AKJxx x Kx AQxxx needs the club finesse on a heart lead, and needs more than that on a diamond lead.
On the second one 4
♠ is better than 3N I think.
My actual hand was AKJ10xx, Axx, void, KQxx, I visualised xx, xx, xxxx, Axxxx (add trash honours to taste to make a 1N response) where 6
♣ is pretty much cold and 7 has play.
Take your pick of which slam you want to be in, if the overcaller is 2551 you want to be in clubs, if he's 1552 you want to be in spades in case his partner has A
♣, I guess you pick 6
♣ in case he's 1651.