Hi Jeremy,
Thanks for your questions!
In terms of what to do before your class, it sounds like you already have a handle on it! Definitely take the math diagnostic that you can find in your student center (you can also find it here:
http://www.manhattangmat.com/foundations-math.cfm ) If the diagnostic says you might do well to attend the workshops, feel free to either watch the recordings of the workshops available in your student center, or sign up for the live workshops at no extra charge.
In addition, make sure you take the first of your practice tests. It's used as a diagnostic, so don't feel worried about how'll you'll do. In fact, you're meant to take it without having studied!
Other than that, really the class is pretty comprehensive, so you should be fine!
As for your second question, when you schedule your exam really depends on how much time you're able to devote to the homework during the course. We often find that students who work full time tend to have trouble finishing all the scheduled work, and like to take about 1-2 months after the course is over to go back over the material that they might not have studied in as much detail as they would have liked. If our students are able to keep up with all the work, we suggest taking 2-3 weeks post-course to review all the material before taking the exam.
Best Wishes,
Caitlin Clay
Student Services Associate
Manhattan GMAT