Thank you so much. Particularly impressed with the explanations for the double on board 1. Seems logical now with hindsight so hopefully also the next time this situation comes up. And also the brilliant and detailed hand reading on board 3, leading to the endplay. Really clever and so instructive.
Board 1: Could have gone for 500 maybe not double dummy but in reality it did. I switched a low heart after two rounds of diamonds, it was ruffed in dummy, spade 7 to the J and Q, and spade 8, 9, T, A setting up my a K6 fork for me. club to the Ace, and a diamond ruffed by declarer to still make a trump. AK of hearts cashed, heart for me, two spades for me and a club for dummy. Still only 100% though... Board 2: I did bid on with 5 clubs, the earlier 4 clubs being a splinter this should be void and should be mandatory queuing from partner, can't see if the message came across as he had no queues. Ended up in 5 spades, same 11 tricks. Board 3: I missed the endplay, nice detection to find it! Board 4: I ducked the diamond K, that led to west shifting Ace and another spade. An easy contract made from there. Board 5: I opened a diamond and rebid 2NT, same 9 tricks in 3NT. Just felt the hand was too strong for a NT opening so decided to treat it as 18-19 balanced. Board 6: I bid 1 spade and 3 clubs over 2 hearts, then 4 clubs after 3 hearts was passed around to me. Disappointed dummy couldn't find the 5th. But still made the 11 tricks. Board 7: Same bidding, same play until the 3rd round of diamonds, I noticed the club 9 discard and then tried a club to the 8. Maybe East would feel the need to cover. But he didn't, West made the club and cashed the spade Ace for my overtrick. Maybe calculated being endplayed. Board 8: Bidding and play copied. Too bad I wasn't awarded 104 % on board 1 for 80% overall ;-)