First, South's opening bid: should he open One Heart or One Diamond, planning either to rebid passively in diamonds, or reverse with his limited point count? With varying degrees of confidence, most Souths ended in Four Hearts after East had overcalled in Clubs and been supported. As you can see, Five Clubs would have been a good sacrifice for East-West, with a good spade guess restricting the loss to 200 points.
It would have been a good sacrifice, however, only if North-South could make Four Hearts. If West ignores his partner's overcall and leads the 4J, the game has no play. Another thought is that if West does decide to lead a club, the king is his best shot - hoping to retain the lead and judge the best continuation.
After a club lead, South's heart game should have been safe. It required careful timing to go down! But losing lines were found at more than one table.
At the table I watched, South ruffed, cashed the !A, then followed with three rounds of diamonds while East discarded clubs. Now a spade lead from West finished matters. As you can see, simply pushing on with the trumps would have ensured 10 tricks