3, If you press "Start", the dice will start shuffling. Then if you press "Stop" , the dice will stop shuffling.
4, About the moment when the number is determined(1). "Pressing [Stop]" is the number is confirmed when you press stop. The result follows the moment of the shuffle numbers. Therefore, I think it's almost impossible, but you can aim for numbers theoretically.
5, About the moment when the number is determined(2)."Press [Start]" is the number is fixed when you press "Start". Therefore, the shuffle is meaningless at all and is just a performance. You can't aim for numbers completely.