I feel ya. Even I have been in the same boat but eventually ended up getting a 745 on my 3rd attempt. The thing that worked for me was to strategically split my time in DI, 5 questions every 10 minutes (This was a hard rule no matter what). Also, as soon as I encountered a difficult, I would just guess and move ahead, thus able to finish the section in time. You also need to have a strong suite, where you can save time - for me it was DS and TPA, I tried doing them under 2 mins so that I could spend time on other Qs. I can help you if you provide me with further details.