Strategy following poor first GMAT score - Quant held me back

Hi all,

Yesterday I took my first shot at the GMAT after spending the last 6 weeks studying (~130 hours or so). I've always struggled with math on standardized tests and so I knew that the GMAT would be no different. However, I hadn't spent much time studying for other exams in the past so I thought that by putting in the time for the GMAT I would be able to overcome this issue. Sadly, I was wrong and I ended up with a 650 (39Q, 41V, 8 IR) which was very disappointing. It isn't really too much outside my range of practice test scores but they also had a pretty wide range based on one far outlier. Here are the practice scores from the last 6 weeks:

GMATPrep Test1 - 680 (42Q, 41V, 8 IR) - April 17th
GMATPrep Test2 - 640 (36Q, 40V, 8 IR) - May 1
GMATPrep Test3 - 730 (48Q, 42V, 8 IR) - May 8
GMATPrep Test 4 - 640 (39Q, 40V, 7 IR) - May 15 --> this shook my confidence a bit and it was 2 days before my real exam

I need to definitely retake the exam, as I need a 730+ to be competitive for the MBA programs I am looking at. Luckily, I just graduated undergrad and so I have ~4-5 years before I would need to have the score, but I would prefer to get it out of the way sooner rather than later. As my test scores show, quant is really what is holding me back so I have a few questions going forward:

1) What would the best resource be to improve my quant ability? I am 100% dedicated to putting in the time and willing to spend the money to get a good score so what would be the best choice out there? My strategy for studying before was reading through each of the Manhattan Quant books once and then doing all of the OG Quant problems and about half of the OG Quant Review book problems. I think the problem with these is that there are too many easy questions so I wasn't getting enough practice on the medium/hard questions where I need to improve. I also kept a detailed error log - my accuracy rates for PS were 76% and for DS it was 68%. There isn't really one area in particular that is a problem, I am around that accuracy rate for each type of question, with geometry being a bit lower.

2) Should I cancel my score? I 100% know that I will not be able to use this score for anywhere I would consider going. I'd guess it would be best having this score not be on my report (might not look good to adcoms), but if there is any other rationale let me know. I've also considered getting the ESR instead of cancelling but I'm not sure how useful it would be.

3) How long should I wait to take the exam again? The nice part of the last 6 weeks is that I've had a gap between school and starting work so I had a lot of free time. I will be starting a job in mid-June so I could potentially try and grind out the next two weeks and retake the GMAT before then, but I'm not sure how much improvement I will see (and I'd rather not waste another $250 for another bad score). I was thinking possibly at the end of summer, but I will also not be able to study a ton as I adjust to my job

Any help from any of you great GMATClub members would be fantastic! GMATClub has been a great resource throughout this whole process. If there is any information I left out that could be helpful, let me know!