Rather than place my thoughts on the hands in the previous post in the comments section, I thought they were interesting enough for a new post.
On hand 1, the juniors were playing Precision so a 1♣ opener was not an option. I also tend to open 1♠ on these 5-5 hands but a natural club opener would have given you an even tougher decision - do you bid 4♠ after 1♠ (1NT) Pass (4♥) - ?
Both pairs were playing methods to allow them to distinguish between good and bad spade raises. I prefer transfers after 1M (Dbl) but some use a redouble to show a good raise.
Like Iain, my initial thought was that 4♠ was clear on this hand but it's not difficult to think of nightmare hands where you will go for a large penalty. In the end I think you just have to ignore these and put 4♠ on the table - it will probably make and some of the time they will save in 5♥. So put the pressure back on them.
On this hand, you can make 10 tricks in spades and they make 9 tricks in hearts.
On hand 2, I think anything could be right. The 6♦ chosen at the table gives partner a chance to raise when it's right (and when it's wrong) and I think that slower routes will only make it more difficult (it was also LotG's choice). The real winner was the 3♥ pre-empt.
As it happens, partner holds the ♦A, a doubleton spade, the ♥K and the ♣K so making all the tricks is simple. Playing in the small slam was still worth 5 IMPs on BBO (as many did not open 1♣).
Hand 3 is also tricky. I agreed with the 4♥ bid chosen - firstly the opposition may not bid over this, as hearts outrank diamonds, whereas bidding diamonds over 5♣ seems more natural; secondly your decision over 5♦ is no easier over whichever you bid, but it might be easier for partner to bid hearts than commit to a club slam.
At the time, most of the kibitzers were for doubling 5♦, but I was pretty confident that 5♥ would eventually be bid. The danger of a double game swing is just too much. Naturally 5♥ was doubled.
You can make 11 tricks in hearts. They will make 9 or 10 tricks in diamonds, depending on whether partner tries to cash the top two clubs. Making 5♥ doubled won 9 IMPs.