Most schools will not raise an eyebrow if they see an applicant who's taken the test 2 times, or sometimes even up to three times. However, I would strongly advise you against taking the test in November if you don't feel adequately prepared--even if it's a trial run. Even though schools consider your highest GMAT score, they will see all your scores. Thus a first attempt that gets you only a 500 even with a second attempt that gets you a 700 might raise a flag (in my opinion).

If you want a decent trial run, I recommend that you use the GMATPrep software, available for free from MBA.com. These tests feature real but retired GMAT questions, and are an excellent simulation of the GMAT. See how you do with these practice tests instead of invest in a first attempt on the real test.

Hope that helps, good luck!

Yes definitely. Always better off just taking the test in one shot (if possible) and doing it right that one time. It does add some pressure on you, but I think it will make you a better candidate in the eyes of the adcoms.

Good luck!