Three answers:

1) I do not think that the documentation covers this topic very well, even though it is very intuitive. That is why I posted the question here.

2) Yes, -8 would have sufficed, but I set it to such a crazy large number to demonstrate a point. I always gets points better when they have crazy large numbers in them. 🙂

3) Yes, the temporary tables end when the session ends. I dropped them because of best practices/force of habit. It's like I tell my children, you have to put away your toys when you are done playing with them.