I have done 8 untimed practice tests in Math Destroyer, taking my time to learn all of them. I just took my first timed Math Destroyer test about an hour ago and I didn't even get close to 50%. I would start practicing timed math A.S.A.P. I consider myself pretty good at math and in studying for the DAT I've come across tons of stuff I've never seen before. Start hitting it hard, you still have time.