Just try not to let nerves get the better of you. I know it's easier said than done but once you're in there it'll fly by. You will be shown all the instruments before you go in and their functions will be clearly explained. The best advice I can offer is the same as I've given before.
1) Early night
2) Good breakfast
3) Relax
Also, it's true that all can go through from one stage 4 day. There were 6 on mine and they all went through. Also, I believe none went through the following week. If you're good enough, you'll do it. Best of luck.