First off all congratulations
I know it's not easy to get a 750 on MGMAT [I haven't been able to pull it off yet!]
However, since you want to be absolutely sure that your score is a true reflection of the improvement you've made, I'd say - take two more Manhattan CATs and see if the score stays within acceptable limits.
Well- i sincerely hope it eventually translates to a 80% + in quant and verbal. Test 2 and test 3 are coming up over the long weekend. I want to brush up the weak areas in the mean time- namely RC in verbal and some topics in quant.
Also, i did not write the AWA in the first test, i may incorporate it in the 3rd test and onwards. I hope i wasnt too fresh because of this! i scored a 6 the previous time.
Keeping my fingers crossed. I know many folks have redone their gmat, im eagerly waiting to hear from them about the retake!