Hi itsmedavidv,
If you want a specific answer from a Veritas employee, then you might want to try posting in that company's Forum (on this site).
When it comes to putting together your plans, you have to allow for some flexibility. You've given yourself 3 months to study, which is good, but you might need more time than that. To that end, what is your score goal? If you wanted a 700, but you scored 640, would you stop studying or continue on and retest?
Until you get some practice in and take some FULL-length practice CATs, there won't be any way to measure your progress, so we won't know exactly when you should schedule your Official GMAT. In general, a date that is approximately 3 months from when you begin your studies is a good initial plan. You can always pay the $50 rescheduling fee and move the date if you choose. You should have plenty of options when it comes to scheduling, since March/April tends to be a slower time of year for Test Takers, which means that you'll likely be able to get a Test Date on a day and time of your choosing without having to schedule several months in advance. You will probably find that scheduling the GMAT (and locking it in to your schedule) will help you to stay focused on the goal though. Having a deadline often helps people to stay on task and work harder.
GMAT assassins aren't born, they're made,
Rich