GC thoughts on my retesting strategy

So after taking a little time away from the GMAT I've regained my testing optimism and have decided to retest. My official test results are 500 overall Q38 V22. That score is truly disappointing and humbling. As part of my new study plan I'm going to reread the MGMAT Series of books starting with my recent purchase if the new MGMAT Foundations of GMAT Verbal.

My results from the GMAT practice questions are as follows, these results are (# correct)/(total number of questions):
Verbal Review, 2nd Ed-> SC: 69/113 RC: 76/104 CR: 59/83
OG11-> SC: 94/138 CR: 80/124 DS: 104/153 PS: 200/249
Quant Review, 2nd Ed-> DS: 80/124 PS: 145/176

My practice test results are as follows, test company/score/date:
1. GMATPrep1: 490, Q(29) V(27), before kaplan test
2. Kaplan: 550, Q(34) V(33), 12/11/10
3. MGMAT1: 520, Q(41) V(21), 12/22/10
4. MGMAT2: 510, Q(32) V(28), 12/26/11
5. Princeton Review: 470, Q(34), V(22) 4/3/11
6. MGMAT3: 550, Q(37) V(29), 4/11/11
7. MGMAT4: 580, Q(44) V(26), 4/20/11
8. GMAT: 500, Q(38) V(22), 4/25/11

I believe that my error in reading the books prior was in part due to me possibly being cocky with my knowledge of math. I started watching the Thursdays with Ron Study Hall sessions and I believe he put it best, this test is an unconventional test and you will be tested on numerous topics in unconventional ways. Although I do have a math background I should have taken notes on every book that I read regardless of my background. And although I can follow the solutions to 95% of Quan questions producing those solutions is quite a different task in a pressure packed testing environment and notes would have given me useful 'takeaways' to study with, as Ron would put it.

Upon further analysis of my practice scores I noticed that I missed numerous question toward the end of every Quan Section and that I do not have a realistic tool for having a feel for when Im over time, outside of looking at the clock. To develop this feel should I just use the GMAT timer for every question and stop/guess at 2/2:30 mins for Quan, 1:30 for SC, etc until I know when Im over/under without it?

Im wondering what the community thinks about my plan to retest. Is there more I can do to change the results of my next test? Im thinking a test date around the first week of September should give me time to improve. Im also considering enrolling in Knewton as I do believe I learn better by having some that I can interact with, ie normal classroom setting. I attended a couple of live sessions during the trial period but I have not clue how the adaptive questions would work. Seems interesting guess I'll make a decision in July. Thanks for all the input its really appreciated!