GMAT in next 10 days - Should I reschedule?

Gmatclubbers,

I really need your advice on above post because I am running out of time. If I have to reschedule the test , I have to do so in next 2 days.

1) I would personally not like anything below 700, meaning thereby I am not going to utilize any score that is less than 700.I will be writing the test again to cross the 700 barrier. Would it make sense to go ahead and still take the test as scheduled on 31st ?

2) Considering that I have not been able to cross the 700 barrier in any of the practice tests so far, Is there still a chance that I can cross 700 on the test day ? Do people generally score more on the actual gmat compared to what they score in gmatprep ?

3) How much time would it take to study for IR. lets say if I reschedule my test for August end. Keeping August reserved for mock tests, would 2 months June & July will be sufficient to improve the score from high 650 range to 720+ while learning IR simultaneously. I can devote 3 hours from Mon to fri and 5 hrs on Sat/Sun.

4) Does experience of having taken the actual gmat once provides any benefit on second attempt ? I mean if I go ahead and take the test now and then I go for second attempt somewhere down the line would I be more confident for second attempt considering that I have actually attempted the GMAT earlier.?
PS: I have taken all my tests under official conditions, So i am not quite sure how much of difference and actual GMAT can bring forward in preparing me further.