I took the MCAT for the first time on December 6th. Notes:
1. As you mentioned, the Physical Sciences did seem heavier on arithmetic and algebra, I will agree with that. PS was my worst time crunch, which was also the case on practice exams. Here are tips: Look at the answer choices before beginning the number crunching. If the answers are spread far apart, then round like crazy to make the math go faster. However, sometimes the answers are not spread so far apart, so this is not universally applicable. Second, save the very slow questions for last. I am fairly certain that all questions are worth an equal amount (except for trial questions which are worth zero), so you should knock off the 30 second questions and come back to the 3 or 4 minute questions.
2. The real MCAT is much more anxiety provoking than the practice exams. On the upside, this means you will not get bored or tired (if you are like me). On the downside, this means you need to practice your deep breathing, muscle relaxation, and mental fortitude. The real MCAT is stressful in so many ways I didn't expect: They pat you down, they make you empty your pockets, you have no water bottle, stuff like that. It is quite reminiscent of being in prison.
3. There is no Trial Section in January, you will not have a Trial Section. The computer will allude to its existence, but then it just won't be there. This is normal (for December and January).