There is another aspect to remember here in addition to the time management. Your bonus points from the class (I assume you did them, if you didn't get started now) apply to your final score. So, you don't have to get everything, you just have to get enough points to add up with your bonus points to pass. I would say don't shoot for 100%, instead, evaluate what you are working with before you start concentrating on anything.
The points are important, but before you set out to own anything, get your recon done. Figure out what you are dealing with. Don't spend more than the allotted time on any one box. Document everything you do, and then if you have extra time once you've gotten other objectives go back and finish. By getting as much info as you can about all the boxes, you have the opportunity for them to determine what amount of credit you get for each objective. If you haven't done anything, there is no room to give you the benefit of the doubt.
CISSP, CSSLP, MCSE+Security, MCTS, CCSP, GPEN, GWAPT, GCWN, NOP, OSCP, Security+