Heres what i say. You are a commercial pilot, you have the knowledge and flying skills, so RELAX. Take your time, study hard, the night before have a beer and go to bed. During your lfight explain, DO NOT TEACH, just explain what your doing, and if you make a mistake explain it, and what happened, thats your get out of jail free card. Also make sure you have your lazy 8s down pat, theyre the hardest of the commercial maneuvers and used the most on checkrides. Have fun, its such a pleasure to fly with the feds!