As Helms99 said, it's really hard to say for sure since everyone has different personalities and learning speeds, but in general, if someone can study about 7-8hrs a day for 6 weeks, scoring well is usually not a problem provided that most of those study hours were productive hours and not much "doodling" was involved haha.
All of the people I know that did the intense 6-8 weeks did great on their DAT!
Good luck!