Playing in a Howell with Gerry came below average with 48%. Weren't doing well about half way through (though better than we thought) without doing anything wrong. We then proceeded to make up for that.
Peter led 5C and my first thought is I don't want a heart switch. If diamond finesse works I have 11 tricks, if clubs 4-4 winning immediately essential to avoid possible heart switch. I certainly need that possibility of 11 tricks so I took Jim's 8C and ran TD for 1 down.
If I had been playing aggregate / teams I would have ducked the club. Expecting a club back that would go to Q and Ace and most players will clear the clubs. Now when you take diamond finesse you are guaranteed the contract, either West has no more clubs or they are 4-4. The danger with that is a heart switch but West would need KQJx(x) hearts and Kx(x) of diamonds to find that. A good East defender might find it after winning second club with Ace (I would be discarding a heart from Dummy) but mostly at aggregate / Butler ducking the club is best.
After 1D - 1NT, North's only suit is clubs. In fact unless they are precisely 3334 they will have 5 clubs. South had no problem jumping to 3NT, how many clubs is your partner likely to have? I would reckon 2 or 1 is to be expected most times. They could have length in diamonds and / or a major. If they hold diamonds that will usually come into the play by Declarer, so a major lead might be best, a heart might be considered but a top spade is possibly what I would have chosen. As you can see out of 5 North's that played 3NT, 3 got a spade lead.
Everyone else led KH, declarer will take the Ace, draw trumps, cash AK of clubs then play a diamond but what do you do?, Finesse and make 13 or go over to Ace, discard heart on QC and make 12? Well at match points everyone went for 13 (possibly 'helped' by East's heart overcall) and so they made 11.