It's been quite a while since I've taken a DSST so I don't remember how the scheduling of the exam works. But, with only TECEPs left to complete my degree and an odd combination of "Wow, I'm almost done! Let's keep this train moving!" and "If I have to study for one more hour I think I'll scream!" I have taken to figuring out a reasonable amount of time for me to prepare for an exam and then scheduling the exam accordingly. I work much better with deadlines. Now I know that on "X date" I have to take the exam so I'd better get cracking!
Best of luck!